JP7165901B2 - scroll compressor - Google Patents

Description

The present disclosure relates to a scroll compressor that compresses a refrigerant gas and is used in, for example, a cooling and heating air conditioner, a refrigerating device such as a refrigerator, or a heat pump type hot water supply device.

A scroll compressor that constitutes a conventional refrigeration system is provided with a back pressure chamber that presses the back surface of the orbiting scroll or the fixed scroll.

An intermediate pressure hole communicating between the back pressure chamber and the compression chamber is provided in the orbiting scroll or the fixed scroll so that the pressure in the back pressure chamber becomes intermediate pressure between the pressure on the suction side and the pressure on the discharge side.

The scroll compressor is provided with an oil supply mechanism that supplies oil to the back pressure chamber by a pressure difference between the pressure on the discharge side in the closed container and the intermediate pressure in the back pressure chamber.

The scroll compressor is provided with a relief hole that communicates between the compression chamber and the discharge side in the closed container, and a relief valve that opens and closes the relief hole according to the pressure difference between the compression chamber and the discharge side in the closed container. there is The relief valve is provided at a position that intermittently communicates the relief hole and the intermediate pressure hole (Patent Document 1).

Further, in a scroll compressor that constitutes a conventional refrigeration system, a flow path having an opening connected to one of a pair of compression chambers and an opening connected to a back pressure chamber is provided in the orbiting scroll or the fixed scroll. ing.

The volume ratio of the compression chamber on the side where the opening on the closed space side of the flow channel is connected is configured to be smaller than the volume ratio of the compression chamber on the side where the opening is not connected (Patent Document 2).

In either configuration, the pressure in the back pressure chamber is an intermediate pressure between the suction pressure and the discharge pressure. Supplying oil from the back pressure chamber to the compression chamber facilitates an increase in the compression chamber pressure.

For this reason, in Patent Document 1, the intermediate pressure hole and the relief hole are communicated to prevent the overcompression state.

Further, in Patent Literature 2, by adjusting the volume ratio of the compression chamber, an increase in required power due to overcompression is suppressed.

Japanese Patent No. 3584781 Japanese Patent No. 4693984

In conventional scroll compressors, overcompression is prevented during high compression ratio operation, which is operation in a state where the compression ratio (ratio of discharge pressure to suction pressure) is relatively high.

Avoiding an overcompression state is effective in reducing the pressure in the compression chamber, but at the same time, the pressure in the back pressure chamber also decreases, which does not lead to stable compression operation. Furthermore, due to the energy saving of air conditioning, refrigeration and lubricating equipment, and compressor rotation speed control technology, scroll compressors are required to operate at a gentler, lower compression ratio. there is

However, in conventional scroll compressors, the pressing force between the orbiting scroll and the fixed scroll is lower than the pushing force from the compression chamber during low compression ratio operation. Therefore, there is a problem that overturning, which is a phenomenon in which the orbiting scroll and the fixed scroll separate, occurs.

The present disclosure has been made in view of the above problems, and provides a scroll compressor that eliminates overturning, which is a phenomenon in which the orbiting scroll separates from the fixed scroll during operation at a low compression ratio, and performs stable compression operation. be.

A scroll compressor of the present disclosure comprises: a fixed scroll having a first end plate and a first spiral wrap; an orbiting scroll having a second end plate and a second spiral wrap; A compression chamber configured by meshing with a scroll and a back pressure chamber holding back pressure for pressing the orbiting scroll against the fixed scroll are provided.

The compression chamber has an outer compression chamber positioned outside the second spiral wrap of the orbiting scroll and an inner compression chamber positioned inside the second spiral wrap of the orbiting scroll. ing.

The back pressure chamber communicates only with the inner compression chamber during compression.

Each of the outer compression chamber and the inner compression chamber has a suction confinement volume at the time when confinement of the working fluid is completed.

The suction containment volume of the outer compression chamber is greater than the suction containment volume of the inner compression chamber.

During compression, the inner compression chamber communicates with the back pressure chamber.

The ratio of the suction confinement volume of the inner compression chamber to the volume of the inner compression chamber when communication between the inner compression chamber and the back pressure chamber is terminated is defined as a back pressure chamber closed volume ratio.

A dischargeable volume ratio is defined as a ratio of the suction confinement volume to the volume of the working fluid that can be discharged to the discharge path when the internal pressure of each of the outer compression chamber and the inner compression chamber rises above the discharge pressure.

The back pressure chamber closed volume ratio is smaller than the dischargeable volume ratio of the inner compression chamber and larger than the dischargeable volume ratio of the outer compression chamber.

With this configuration, during low compression ratio operation when the compression ratio becomes smaller than the volume ratio when the back pressure chamber is closed, overcompression occurs in the inner compression chamber on the side to which the back pressure chamber communicates, and the back pressure chamber is also interlocked. Over-compressed.

After that, the communication between the back pressure chamber and the compression chamber is closed, and the compression chamber drops to the discharge pressure when the dischargeable volume ratio is reached. On the other hand, since the back pressure chamber is separated from the compression chamber, it maintains an overcompressed state.

Therefore, the orbiting scroll is pressed against the fixed scroll by the pressure in the back pressure chamber that is equal to or higher than the discharge pressure, and it is possible to suppress overturning.

Advantageous Effects of Invention According to the present disclosure, it is possible to provide a scroll compressor that eliminates the separation of the orbiting scroll from the fixed scroll and performs a stable compression operation during operation at a low compression ratio.

FIG. 1 is a side sectional view of a scroll compressor according to an embodiment of the present disclosure. FIG. 2 is an enlarged cross-sectional view of a main part of the compression mechanism of the scroll compressor. 3 is a cross-sectional view taken along line CC in FIG. 2. FIG. FIG. 4 is a diagram showing the opening state of the communication passage with the back pressure chamber and the injection port accompanying the orbital motion of the scroll compressor. FIG. 5 is a diagram for explaining the positional relationship between the communication passage with the back pressure chamber and the seal member accompanying the orbital motion of the scroll compressor. FIG. 6 is a refrigeration cycle diagram using a scroll compressor according to an embodiment of the present disclosure. 7 is a cross-sectional view taken along line AA in FIG. 2. FIG. 8 is a cross-sectional view taken along the line BB in FIG. 7. FIG.

A scroll compressor of the present disclosure comprises: a fixed scroll having a first end plate and a first spiral wrap; an orbiting scroll having a second end plate and a second spiral wrap; The scroll compressor is provided with a compression chamber configured by meshing with a scroll, and a back pressure chamber holding back pressure for pressing the orbiting scroll against the fixed scroll.

The compression chamber has an outer compression chamber positioned outside the second spiral wrap of the orbiting scroll and an inner compression chamber positioned inside the second spiral wrap of the orbiting scroll. ing.

The back pressure chamber communicates only with the inner compression chamber during compression.

Each of the outer compression chamber and the inner compression chamber has a suction confinement volume at the time when confinement of the working fluid is completed.

The suction containment volume of the outer compression chamber is greater than the suction containment volume of the inner compression chamber.

During compression, the inner compression chamber communicates with the back pressure chamber.

The ratio of the suction confinement volume of the inner compression chamber to the volume of the inner compression chamber when communication between the inner compression chamber and the back pressure chamber is terminated is defined as a back pressure chamber closed volume ratio.

A dischargeable volume ratio is defined as a ratio of the suction confinement volume to the volume of the working fluid that can be discharged to the discharge path when the internal pressure of each of the outer compression chamber and the inner compression chamber rises above the discharge pressure.

The back pressure chamber closed volume ratio is smaller than the dischargeable volume ratio of the inner compression chamber and larger than the dischargeable volume ratio of the outer compression chamber.

With this configuration, during low compression ratio operation when the compression ratio becomes smaller than the volume ratio when the back pressure chamber is closed, overcompression occurs in the inner compression chamber on the side to which the back pressure chamber communicates, and the inner side on the side to which the back pressure chamber communicates. The back pressure chamber is also overcompressed in conjunction with the compression chamber. After that, the communication between the back pressure chamber and the inner compression chamber is closed, and the inner compression chamber drops to the discharge pressure when the dischargeable volume ratio is reached. On the other hand, since the back pressure chamber is separated from the compression chamber, it maintains an overcompressed state. Therefore, the orbiting scroll is pressed against the fixed scroll by the pressure in the back pressure chamber that is equal to or higher than the discharge pressure, and it is possible to suppress overturning.

Also, a discharge chamber from which the working fluid that reaches the discharge pressure is discharged, a discharge port provided in the center portion of the fixed scroll, and the outer compression chamber provided in the outer compression chamber prior to the discharge port. and a discharge bypass port communicating with the discharge chamber. Further, the discharge bypass port may make the dischargeable volume ratio of the outer compression chamber smaller than the dischargeable volume ratio of the inner compression chamber.

As a result, the inner compression chamber on the side communicating with the back pressure chamber communicates with the discharge port or the discharge bypass port after the communication with the back pressure chamber is closed, and is released from the overcompressed state and lowered to the discharge pressure. On the other hand, the pressure in the back pressure chamber is higher than the discharge pressure because it maintains an over-compressed state with no destination for the pressure to escape. Therefore, a pressing force acts on the orbiting scroll from the side of the back pressure chamber to the side of the fixed scroll, and the compression operation can be continued while maintaining the airtightness of the compression chamber.

Further, by providing the discharge bypass port, regardless of the wrap shape of the orbiting scroll and the wrap shape of the fixed scroll, it is possible to arbitrarily adjust the dischargeable volume ratio of only one of the inner compression chamber and the outer compression chamber. The dischargeable volume ratio of each compression chamber that realizes the present disclosure can be configured with respect to the closed volume ratio of the back pressure chamber.

Further, the back pressure chamber when the communication between the back pressure chamber and the inner compression chamber ends may be a closed space separated from another space having a pressure difference from the back pressure chamber. good.

As a result, a pressing force acts on the orbiting scroll from the side of the back pressure chamber toward the side of the fixed scroll, and the compression operation can be continued while maintaining the airtightness of the compression chamber.

Embodiments of the present disclosure will be described below with reference to the drawings. Note that the present disclosure is not limited by these embodiments.

(Embodiment)
FIG. 1 is a side cross-sectional view of a scroll compressor according to an embodiment of the present disclosure, and FIG. 2 is an enlarged cross-sectional view of a main part of a compression mechanism of the scroll compressor.

The operation and action of the scroll compressor according to the present embodiment will be described below.

As shown in FIG. 1, a scroll compressor 91 according to the present embodiment includes a closed container 1, a compression mechanism 2 located inside the closed container 1, a motor unit 3 for driving the compression mechanism 2, a closed container 1 and an oil reservoir 20 provided at the bottom.

As shown in FIG. 2, the compression mechanism 2 includes a main bearing member 11 fixed in the sealed container 1 by welding or shrink-fitting, and bolted onto the main bearing member 11 to provide an end plate (first end plate). A fixed scroll 12 with a spiral wrap (first spiral wrap) standing upright on the front, and an orbiting scroll 13 with a spiral wrap (second spiral wrap) standing upright on the end plate (second end plate). It has The compression mechanism 2 includes a compression chamber 15 formed by meshing the fixed scroll 12 and the orbiting scroll 13 , and a back pressure chamber 29 that holds the pressure that presses the orbiting scroll 13 against the fixed scroll 12 .

Between the orbiting scroll 13 and the main bearing member 11, a rotation restraining mechanism 14 including an Oldham ring or the like is provided to prevent the orbiting scroll 13 from rotating and to guide the orbiting scroll 13 in circular orbital motion.

The shaft 4 is rotationally driven by the motor section 3 . The shaft 4 is supported by a main bearing member 11 , and the orbiting scroll 13 is eccentrically driven by an eccentric shaft portion 4 a at the upper end of the shaft 4 .

As a result, the orbiting scroll 13 moves in a circular orbit. A compression chamber 15 formed between the fixed scroll 12 and the orbiting scroll 13 moves from the outer peripheral side toward the central portion while shrinking its volume. Utilizing this, the working fluid is sucked from the suction pipe 16 (see FIG. 1) leading to the outside of the sealed container 1 and the suction port 17 on the outer peripheral portion of the fixed scroll 12, and after being confined in the compression chamber 15, Compressed.

The working fluid that reaches a predetermined pressure pushes open a discharge reed valve 19 from a discharge port 18 provided in the center of the fixed scroll 12 . The working fluid that reaches the discharge pressure passes through the discharge chamber 31, is discharged into the sealed container 1, and is sent out of the sealed container 1 through the discharge pipe 22 (see FIG. 1).

As shown in FIG. 1, a pump 25 is provided at the lower end of the shaft 4. As shown in FIG. The pump 25 is arranged such that its suction port is within the reservoir 20 . The pump 25 is driven simultaneously with the orbiting scroll 13 . As a result, the pump 25 can reliably suck up the oil 6 in the oil reservoir 20 regardless of pressure conditions and operating speed. Therefore, there is no possibility of running out of oil.

The oil 6 sucked up by the pump 25 is supplied to the compression mechanism 2 through an oil supply hole 26 passing through (through) the shaft 4 .

By removing foreign matter from the oil 6 with an oil filter or the like before or after the oil 6 is sucked up by the pump 25, foreign matter can be prevented from entering the compression mechanism 2, thereby further improving reliability. can.

The pressure of the oil 6 led to the compression mechanism 2 is substantially the same as the discharge pressure of the scroll compressor 91 and serves as a back pressure source for the orbiting scroll 13 . Further, part of the oil 6 seeks a place of escape by the supply pressure and its own weight, and flows into the fitting portion between the eccentric shaft portion 4a and the orbiting scroll 13 and the bearing between the shaft 4 and the main bearing member 11. After entering the portion 66 and lubricating each portion, it drops and returns to the oil storage portion 20 .

3 is a cross-sectional view taken along the line CC in FIG. 2. FIG.

The compression chamber 15 formed by the fixed scroll 12 and the orbiting scroll 13 includes an outer compression chamber 15a positioned outside the wrap of the orbiting scroll 13 and an inner compression chamber 15b positioned inside the wrap.

The scroll compressor 91 is an asymmetric scroll compressor in which the suction entrapment volume of the outer compression chamber 15a and the suction entrapment volume of the inner compression chamber 15b are different.

Here, the intake confinement volume is the volume of the compression chamber immediately after confining the working fluid sucked from the intake port 17 . Furthermore, the scroll compressor 91 is an asymmetric scroll compressor in which the suction entrapment volume of the outer compression chamber 15a is greater than the suction entrapment volume of the inner compression chamber 15b.

Since the asymmetric scroll compressor increases the suction confinement volume of the compressor as a whole, the space inside the compressor can be used efficiently.

Also, the working fluid sucked from the suction port 17 can be confined in the vicinity of the suction port 17 in the outer compression chamber 15a to enter the compression process. Therefore, the low-pressure, low-temperature working fluid is heated by the compression mechanism 2, and a decrease in the density of the working fluid can be suppressed.

The difference in suction confinement volume between the outer compression chamber 15a and the inner compression chamber 15b affects the volume ratio. The volumetric ratio is the ratio of the suction containment volume to the volume of the compression chamber at any point in the compression stroke. A volume ratio can be defined for each of the outer compression chamber and the inner compression chamber.

Generally, when the inner compression chamber and the outer compression chamber communicate with the discharge port 18 provided in the central portion of the fixed scroll 12, the compression chamber volumes are substantially equal. If the discharge port 18 is the only exhaust path for working fluid in the compression chambers, the dischargeable volume ratio of each compression chamber is determined by the suction confined volume.

Here, the dischargeable volume ratio is the ratio of the suction confined volume to the volume of the compression chamber when the compression chamber becomes capable of discharging, that is, when the compression chamber and the discharge chamber 31 communicate with each other. The dischargeable volume ratio can be defined for each of the outer compression chamber and the inner compression chamber.

In the present embodiment, the suction confinement volume of the outer compression chamber 15a is larger than the suction confinement volume of the inner compression chamber 15b. The available volume ratio is increased.

During low compression ratio operation, which is operation with a relatively low compression ratio, the outer compression chamber 15a is more likely to be overcompressed than the inner compression chamber 15b. Here, the compression ratio is the ratio of discharge pressure to suction pressure. Further, the outer compression chamber 15a has a larger area when projected in the pressing direction than the inner compression chamber 15b. Therefore, the excessive compression of the outer compression chamber 15 a tends to increase the force pushing the orbiting scroll 13 away from the fixed scroll 12 .

In addition, based on the results of measuring the temperature distribution during operation, the winding end portion 13c (see FIG. 2) of the orbiting scroll 13 gradually increases from the winding start portion, which is the central portion, to the winding end portion, which is the outer peripheral portion. A slope shape is provided to increase the wrap height. This makes it possible to absorb dimensional changes due to thermal expansion and prevent local sliding.

As shown in FIG. 2, the scroll compressor 91 includes a connection path 55-1 and a supply path 55-2 as an oil supply path 55 for guiding oil from the oil reservoir 20 to the compression chamber 15. As shown in FIG.

Further, as an oil supply route to the compression chamber 15, a passage 13a formed inside the orbiting scroll 13 and a recess 12a formed in the end plate of the fixed scroll 12 on the wrap surface side are provided. Passage 13a includes supply passage 55-2.

One open end 55-2b of the passage 13a is formed at the wrap tip 13c and periodically opens into the recess 12a in accordance with the turning motion. Also, the other open end 55-2a of the passage 13a always opens into the back pressure chamber 29. As shown in FIG. As a result, the back pressure chamber 29 intermittently communicates only with the inner compression chamber 15b and does not communicate with the outer compression chamber 15a.

In addition, by positively supplying oil to the inner compression chamber 15b having a high rate of pressure rise, the inner compression chamber 15b-1 (see FIG. 3) formed one before in the compression process is replaced by the inner compression chamber 15b-1 (see FIG. 3) formed next. Leakage to the inner compression chamber 15b-2 (see FIG. 3) can be suppressed.

Further, as shown in FIG. 2, on the back surface 13e of the orbiting scroll 13, a sealing member 78, a high-pressure region 30 for holding working fluid at a discharge pressure, and a working fluid at a pressure intermediate between the discharge pressure and the suction pressure are provided. A back pressure chamber 29 for holding is provided. The sealing member 78 partitions the inside of the sealing member 78 into the high pressure region 30 and the outside of the sealing member 78 into the back pressure chamber 29, respectively.

At least one of the oil supply paths is configured to pass through the back pressure chamber 29 . That is, the oil supply path 55 is composed of a connection path 55-1 from the high pressure region 30 to the back pressure chamber 29 and a supply path 55-2 from the back pressure chamber 29 to the inner compression chamber 15b.

As a result, the orbiting scroll 13 is stably pressed against the fixed scroll 12 by the back pressure from the back surface 13e. can be done.

Further, by using the seal member 78, the pressure in the high pressure region 30 and the pressure in the back pressure chamber 29 (hereinafter referred to as back pressure) are completely separated, and the pressure applied from the back surface of the orbiting scroll 13 can be stably applied. You can control it.

Further, by providing the connection path 55-1 from the high pressure region 30 to the back pressure chamber 29, the oil 6 can be supplied to the sliding portion of the rotation restraint mechanism 14 and the thrust sliding portion between the fixed scroll 12 and the orbiting scroll 13. can supply.

Further, by providing the supply path 55-2 from the back pressure chamber 29 to the inner compression chamber 15b, the amount of oil supplied to the inner compression chamber 15b can be positively increased, and the leakage loss in the inner compression chamber 15b can be suppressed. .

Also, one open end 55-1b of the connection path 55-1 is formed on the back surface 13e of the orbiting scroll 13, and the seal member 78 is passed therethrough, and the other open end 55-1a is always open to the high pressure region 30. Let Thereby, intermittent oil supply and adjustment of back pressure can be realized.

First, intermittent oil supply will be explained.

FIG. 5 is a diagram for explaining the positional relationship between the communicating path with the back pressure chamber and the seal member accompanying the orbital motion of the scroll compressor.

FIG. 5 shows the states of (I) 0° to 90°, (II) 90° to 180°, (III) 180° to 270°, and (IV) 270° to 360° by shifting the phase by 90 degrees. showing.

That is, FIG. 5(II) shows the state where the shaft 4 is rotated 90 degrees from FIG. 5(I), FIG. 5(III) shows the state where FIG. (IV) of FIG. 5 shows a state further rotated by 90 degrees from (III) of FIG. 5, and (I) of FIG. 5 shows a state further rotated by 90 degrees from (IV) of FIG.

As shown in FIG. 5, one open end 55-1b of the connection path 55-1 is positioned on the back surface 13e of the orbiting scroll 13. As shown in FIG. A back surface 13 e of the orbiting scroll 13 is partitioned by a seal member 78 into an inner high pressure area 30 and an outer back pressure chamber 29 .

In the state of (II) in FIG. 5, one open end 55-1b is open to the back pressure chamber 29 outside the seal member 78. As shown in FIG. Therefore, the back pressure chamber 29 and the high pressure region 30 are communicated with each other. As a result, the oil 6 is supplied from the high pressure region 30 to the back pressure chamber 29 .

On the other hand, in the states (I), (III), and (IV) of FIG. 5, the open end 55-1b opens inside the seal member 78. Therefore, the back pressure chamber 29 does not communicate with the high pressure region 30 . Therefore, the oil 6 is not supplied from the high pressure region 30 to the back pressure chamber 29 .

That is, one open end 55-1b of the connection path 55-1 travels between the high pressure region 30 and the back pressure chamber 29, and the opening ends 55-1a and 55-1b on both sides of the connection path 55-1 are connected. Oil 6 is supplied to the back pressure chamber 29 only when a pressure difference occurs between them. As a result, the amount of oil to be supplied is adjusted according to the time ratio during which one open end 55-1b moves back and forth across the seal member 78. As shown in FIG. Therefore, the passage diameter of the connecting passage 55-1 can be configured to be 10 times or more the diameter of the oil filter.

In addition, since there is no risk of clogging the passage due to foreign matter getting caught in it, it is possible to apply a stable back pressure, and at the same time, the lubrication of the thrust sliding portion and the rotation restraint mechanism 14 can be maintained in a good state, resulting in high efficiency and high efficiency. High reliability can be achieved.

In the above description, the other open end 55-1a is always in the high pressure region 30, and the one open end 55-1b moves back and forth between the high pressure region 30 and the back pressure chamber 29 as an example. did. The present disclosure is not limited to this example, and for example, the other open end 55-1a travels between the high pressure region 30 and the back pressure chamber 29, and the one open end 55-1b is always in the back pressure chamber 29. Even in this case, since a pressure difference is generated between the open ends 55-1a and 55-1b, intermittent oil supply can be realized and the same effect can be obtained.

Next, the adjustment of the back pressure will be explained.

FIG. 4 is a diagram showing the open state of the communication passage with the back pressure chamber and the injection port accompanying the orbital motion of the scroll compressor.

FIG. 4 shows a state in which the fixed scroll 12 and the orbiting scroll 13 are meshed with each other and viewed from the rear surface 13e of the orbiting scroll 13, and the phases are shifted by 90 degrees. Similar to FIG. 5, FIG. 4 shows the states of (I) 0° to 90°, (II) 90° to 180°, (III) 180° to 270°, and (IV) 270° to 360°. there is

That is, FIG. 4(II) shows the state where the shaft 4 is rotated 90 degrees from FIG. 4(I), FIG. 4(III) shows the state where FIG. (IV) of FIG. 4 shows a state further rotated by 90 degrees from (III) of FIG. 4, and (I) of FIG. 4 shows a state further rotated by 90 degrees from (IV) of FIG.

The state shown in FIG. 4(I) is the position where the outer compression chamber 15a confines the working fluid, and the state shown in FIG. 4(III) is the position where the inner compression chamber 15b confines the working fluid.

In the state shown in FIG. 4I, two outer compression chambers 15a are formed. The outer compression chamber 15a located on the outer peripheral side is in a low pressure state immediately after confining the working fluid, and the outer compression chamber 15a located on the inner peripheral side is in an intermediate pressure state.

In the state shown in FIG. 4(II), the outer compression chamber 15a formed on the inner peripheral side is in a high pressure state before discharge.

In the state shown in FIG. 4(III), two inner compression chambers 15b are formed. The located inner compression chamber 15b is in an intermediate pressure state.

In the state shown in FIG. 4(IV), the inner compression chamber 15b formed on the inner peripheral side is in a high pressure state before discharge.

First, the case of high compression ratio operation will be described.

In the state of (IV) in FIG. 4, one open end 55-2b opens into the recess 12a. Therefore, the inner compression chamber 15 b communicates with the back pressure chamber 29 . During high compression ratio operation, the oil 6 is supplied from the back pressure chamber 29 to the inner compression chamber 15b through the supply passage 55-2 and the passage 13a (see FIG. 2).

The recess 12a is provided at a position where one open end 55-2b opens immediately after the inner compression chamber 15b confines the sucked working fluid (also referred to as the sucked refrigerant) (see (IV) in FIG. 4). ). In other words, one open end 55-2b allows the oil supply path to open to the inner compression chamber 15b during the compression process after the drawn refrigerant is confined. Therefore, the pressure of the back pressure chamber 29 while communicating with the inner compression chamber 15b becomes substantially equal to the pressure of the inner compression chamber 15b.

On the other hand, in the states (I), (II), and (III) of FIG. 4, one open end 55-2b does not open into the recess 12a. Therefore, the oil 6 is not supplied from the back pressure chamber 29 to the inner compression chamber 15b. Also, the pressure in the back pressure chamber 29 is not affected by the inner compression chamber 15b.

Further, as described above, in the state of (II) in FIG. 5 corresponding to (II) in FIG. 4, the back pressure chamber 29 and the high pressure region 30 communicate with each other. As a result, the pressure in the back pressure chamber 29 becomes equal to the pressure in the high pressure region 30, that is, the discharge pressure.

That is, during high compression ratio operation, the pressure in the back pressure chamber 29 can be adjusted to an intermediate pressure state between the suction pressure and the discharge pressure, and this pressure functions as a pressing force against the orbiting scroll during low compression ratio operation.

Next, the case of low compression ratio operation will be described.

During low-compression-ratio operation, in the state of (IV) in FIG. The pressure is higher than the discharge pressure.

In the state of (IV) in FIG. 5, the back pressure chamber 29 does not communicate with the high pressure region 30, and the space formed by the inner compression chamber 15b and the back pressure chamber 29 is a closed space. Therefore, the back pressure chamber 29 is in a higher pressure state than the high pressure region 30 equal to the discharge pressure.

As the compression process progresses further, the open end 55-2b communicating between the back pressure chamber 29 and the inner compression chamber 15b is removed from the recess 12a, and the back pressure chamber 29 becomes an independent closed space. Therefore, the pressure in the back pressure chamber 29 does not depend on the pressure in the inner compression chamber 15 b and the pressure in the high pressure region 30 . When the pressure in the inner compression chamber 15b is compressed to the dischargeable volume ratio or more, the working fluid inside the compression chamber is discharged to the discharge chamber 31, and the pressure drops to the discharge pressure. On the other hand, the pressure in the back pressure chamber 29 remains in the overcompressed state when separated from the inner compression chamber 15b until the back pressure chamber 29 communicates with the inner compression chamber 15b or the high pressure region 30 again.

That is, during low compression ratio operation, only the back pressure chamber 29 maintains a pressure state higher than the discharge pressure in the state of (I) of FIG. 4 and (I) of FIG. It functions as a pressing force to the orbiting scroll.

The scroll compressor 91 is provided with a discharge bypass port 21 (see FIG. 2) in addition to the discharge port 18 as a passage for guiding the working fluid compressed in the compression chamber 15 to the discharge chamber 31 .

The discharge bypass port 21, like the discharge port 18, has a reed valve. When the pressure in the compression chamber 15 reaches the pressure in the discharge chamber 31 , the reed valve is pushed open and the working fluid is discharged to the discharge chamber 31 . When the pressure in the compression chamber 15 is less than the pressure in the discharge chamber 31 , the reed valve is closed to suppress backflow of working fluid from the discharge chamber 31 to the compression chamber 15 .

However, as a condition for the discharge bypass port 21 to achieve the functions described above, the discharge bypass port 21 must exist at a position communicating with the compression chamber 15 . The discharge bypass port 21 is a fixed passage provided in the end plate of the fixed scroll 12 .

The compression chamber 15 moves toward the center while reducing its volume along with the compression operation. can be discharged to the discharge chamber 31 .

The discharge bypass port 21 is provided to allow communication between the compression chamber 15 before communicating with the discharge chamber 31 through the discharge port 18 and the discharge chamber 31 in the compression process.

As shown in FIG. 4, the scroll compressor 91 is separately provided with a discharge bypass port 21a with which the outer compression chamber 15a communicates and a discharge bypass port 21b with which the inner compression chamber 15b communicates. timing is shifted.

The discharge bypass port 21a does not communicate with the outer compression chamber 15a in the state of (I) in FIG. It is provided in the position which communicates.

The discharge bypass port 21b does not communicate with the inner compression chamber 15b in the state of (IV) in FIG. It is provided in the position which communicates.

The outer compression chamber 15a completes the suction stroke at the timing of (I) in FIG. 4, and the inside of the outer compression chamber 15a is confined. At (II) in FIG. 4, where the compression stroke has progressed by 90°, the outer compression chamber 15a is already in communication with the discharge bypass port 21a. In this case, the dischargeable volume ratio of the outer compression chamber 15a is determined by the ratio of the suction confined volume of the outer compression chamber 15a to the compression chamber volume at the timing when the outer compression chamber 15a communicates with the discharge bypass port 21a. , and does not depend on the communication timing with the discharge port 18 .

On the other hand, the inner compression chamber 15b completes the suction stroke at the timing of (III) in FIG. 4, and the inside of the inner compression chamber 15b is confined. In (IV) of FIG. 4, in which the compression stroke has progressed by 90°, the inner compression chamber 15b does not communicate with the discharge bypass port 21b. In FIG. 4(I), which is further advanced by 90°, the inner compression chamber 15b communicates with the discharge bypass port 21b. At the timing of (IV) in FIG. 4, the inner compression chamber 15b communicates with the back pressure chamber 29 through the supply passage 55-2 and the passage 13a.

Also in this case, the dischargeable volume ratio of the inner compression chamber 15b is determined by the communication timing with the discharge bypass port 21b. The dischargeable volume ratio of the inner compression chamber 15b to which the back pressure chamber 29 communicates is larger than the dischargeable volume ratio of the back pressure chamber closed time and the dischargeable volume ratio of the outer compression chamber 15a.

Here, the volume ratio when the back pressure chamber is closed means that the communication between the back pressure chamber 29 and the inner compression chamber 15b in the middle of compression is completed in the compression chamber on the side to which the back pressure chamber 29 communicates, that is, the inner compression chamber 15b. It is the ratio of the suction confinement volume to the volume of the inner compression chamber 15b on the outer peripheral side at the time of (that is, the timing immediately after (IV) in FIG. 4).

With such a configuration, even if the pressure in the compression chamber 15 reaches the discharge pressure at an early timing during low compression ratio operation, the outer compression chamber 15a having a large projected area is not overcompressed and operates to the discharge chamber 31. Fluid can be discharged.

On the other hand, excessive compression occurs in the inner compression chamber 15b, and the pressure is transmitted to the back pressure chamber 29, increasing the pressing force of the orbiting scroll 13. As shown in FIG. After the communication between the inner compression chamber 15b and the back pressure chamber 29 is terminated, the overcompressed pressure of the back pressure chamber 29 is maintained.

On the other hand, excessive compression of the inner compression chamber 15b is eliminated by communication with the discharge bypass port 21b. As a result, the orbiting scroll 13 is stabilized to the fixed scroll 12 by applying a strong pressing force to the back surface 13e of the orbiting scroll while suppressing the force from the compression chamber 15 side acting in the direction of separating the orbiting scroll 13 from the fixed scroll 12. The compression motion can be continued while pressing down.

Next, a refrigeration cycle device using the scroll compressor 91 will be described.

FIG. 6 is a refrigeration cycle diagram using a scroll compressor according to an embodiment of the present disclosure.

As shown in FIG. 6, the refrigeration cycle system includes a scroll compressor 91, a condenser 92, an evaporator 93, two pressure reducers 94, an injection pipe 95, and a gas-liquid separator 96. The scroll compressor 91, the condenser 92, the upstream decompressor 94a, the gas-liquid separator 96, and the downstream decompressor 94b are annularly connected by piping. The injection pipe 95 connects the gas-liquid separator 96 and the scroll compressor 91 .

The working fluid (hereinafter also referred to as refrigerant) condensed by the condenser 92 is decompressed to an intermediate pressure by an upstream decompressor 94 a and flows into the gas-liquid separator 96 . The gas-liquid separator 96 separates the intermediate pressure refrigerant into a gas phase component (gas refrigerant) and a liquid phase component (liquid refrigerant). The intermediate-pressure liquid refrigerant passes through the pressure reducer 94 on the further downstream side, becomes low-pressure refrigerant, and flows into the evaporator 93 .

The liquid refrigerant that has flowed into the evaporator 93 is evaporated by heat exchange and discharged as gas refrigerant or gas refrigerant partially mixed with liquid refrigerant. Refrigerant discharged from the evaporator 93 flows into the compression chamber 15 of the scroll compressor 91 .

On the other hand, the intermediate-pressure gas refrigerant separated by the gas-liquid separator 96 passes through the injection pipe 95 and is injected into the compression chamber 15 inside the scroll compressor 91 . The injection tube 95 may be provided with means for regulating and stopping the injection pressure, such as a block valve or pressure reducer 94 .

In the compression process of compressing the low-pressure refrigerant flowing from the evaporator 93, the scroll compressor 91 injects the intermediate-pressure refrigerant of the gas-liquid separator 96 into the compression chamber 15 to compress the refrigerant, and discharges the high-temperature and high-pressure refrigerant to the discharge pipe. 22 (see FIG. 1) to condenser 92 .

The ratio of the gas phase component and the liquid phase component of the refrigerant separated by the gas-liquid separator 96 will be described.

The greater the pressure difference between the inlet side pressure and the outlet side pressure of the expansion valve (reducer 94a) on the upstream side, the more the gas phase component. Also, the gas phase component increases as the degree of supercooling of the refrigerant at the outlet of the condenser 92 decreases or as the dryness thereof increases.

On the other hand, the amount of refrigerant sucked by the scroll compressor 91 through the injection pipe 95 increases as the intermediate pressure increases. When more refrigerant than the gas phase component ratio of the refrigerant separated by the gas-liquid separator 96 is sucked from the injection pipe 95, the gas refrigerant in the gas-liquid separator 96 is exhausted, and the liquid refrigerant flows into the injection pipe 95. .

In order to maximize the performance of the scroll compressor 91 , it is desirable that the gas refrigerant separated by the gas-liquid separator 96 is completely sucked into the scroll compressor 91 from the injection pipe 95 . If the state of equilibrium is lost, the liquid refrigerant flows from the injection pipe 95 into the scroll compressor 91 . Therefore, even when the liquid refrigerant flows from the injection pipe 95, the scroll compressor 91 must be configured to maintain high reliability.

7 is a cross-sectional view taken along the line AA in FIG. 2. FIG. 8 is a cross-sectional view taken along line BB of FIG. 7. FIG.

At the intermediate pressure flowing from the injection pipe 95, as shown in FIGS. 1, 2, 7 and 8, the refrigerant flows into the intermediate pressure chamber 41, opens the check valve 42 provided in the injection port 43, It is injected into the compression chamber 15 after confinement. The injected refrigerant is discharged from the discharge port 18 into the sealed container 1 together with the refrigerant sucked from the suction port 17 .

An injection port 43 for injecting intermediate-pressure refrigerant is provided through the end plate of the fixed scroll 12 . The injection port 43 opens sequentially to the outer compression chamber 15a and the inner compression chamber 15b. The injection port 43 is provided at a position that opens to each compression chamber during the compression process after confinement in each of the outer compression chamber 15a and the inner compression chamber 15b.

As shown in FIGS. 1 and 2 , the scroll compressor 91 is provided with an intermediate pressure chamber 41 that guides the intermediate pressure working fluid sent from the injection pipe 95 and before being injected into the compression chamber 15 .

The intermediate pressure chamber 41 is formed by a fixed scroll 12, which is a compression chamber dividing member, an intermediate pressure plate 44, and an intermediate pressure cover 45 (see FIG. 2). The intermediate pressure chamber 41 and the compression chamber 15 are
They face each other with the fixed scroll 12 interposed therebetween.

The intermediate pressure chamber 41 has an intermediate pressure chamber inlet 41a into which intermediate pressure working fluid flows, an injection port inlet 43a of an injection port 43 that injects the intermediate pressure working fluid into the compression chamber 15, and a position lower than the intermediate pressure chamber inlet 41a. and a formed liquid reservoir 41b.

The liquid reservoir 41 b is formed on the upper surface of the end plate of the fixed scroll 12 .

The intermediate pressure plate 44 is provided with a check valve 42 that prevents reverse flow of refrigerant from the compression chamber 15 to the intermediate pressure chamber 41 . When the internal pressure of the compression chamber 15 is higher than the intermediate pressure of the injection port 43 in the section where the injection port 43 opens to the compression chamber 15 , the refrigerant flows backward from the compression chamber 15 toward the intermediate pressure chamber 41 . By providing the check valve 42 in this way, the backflow of the refrigerant can be prevented.

In the scroll compressor 91 according to the present embodiment, the check valve 42 is composed of a reed valve 42a that lifts toward the compression chamber 15 and allows the compression chamber 15 and the intermediate pressure chamber 41 to communicate with each other. Therefore, the intermediate pressure chamber 41 can be communicated with the compression chamber 15 only when the internal pressure of the compression chamber 15 is lower than the pressure of the intermediate pressure chamber 41 .

By using the reed valve 42a, there are few sliding parts in the movable part, the sealing performance can be maintained for a long period of time, and the flow passage area can be easily expanded as necessary.

If the check valve 42 is not provided or if the check valve 42 is provided in the injection pipe 95, the refrigerant in the compression chamber 15 flows backward to the injection pipe 95, resulting in wasted compression power consumption. In this embodiment, the check valve 42 is provided on the intermediate pressure plate 44 near the compression chamber 15 to suppress backflow from the compression chamber 15 .

The upper surface of the end plate of the fixed scroll 12 is positioned lower than the intermediate pressure chamber inlet 41a. The upper surface of the end plate of the fixed scroll 12 is provided with a liquid reservoir 41b in which liquid-phase refrigerant is accumulated.

The injection port inlet 43a is provided at a position higher than the height of the intermediate pressure chamber inlet 41a. Therefore, of the intermediate-pressure working fluid, the gas-phase component refrigerant is led to the injection port 43, and the liquid-phase component refrigerant accumulated in the liquid reservoir 41b is vaporized on the surface of the fixed scroll 12, which is in a high temperature state. , the refrigerant of the liquid phase component is difficult to flow into the compression chamber 15 .

Further, the intermediate pressure chamber 41 and the discharge chamber 31 are provided at positions adjacent to each other with the intermediate pressure plate 44 interposed therebetween. As a result, the vaporization of the liquid-phase component of the working fluid flowing into the intermediate pressure chamber 41 is promoted, and the temperature rise of the high-pressure refrigerant in the discharge chamber 31 can be suppressed. Therefore, the operation can be performed up to a higher discharge pressure condition.

The intermediate-pressure refrigerant introduced to the injection port 43 pushes open the reed valve 42 a due to the pressure difference between the injection port 43 and the compression chamber 15 , and joins the low-pressure refrigerant sucked from the suction port 17 in the compression chamber 15 .

The intermediate-pressure refrigerant remaining in the injection port 43 between the check valve 42 and the compression chamber 15 repeats re-expansion and re-compression, which causes the efficiency of the scroll compressor 91 to decrease. Therefore, the thickness of the valve stop 42b, which regulates the maximum displacement of the reed valve 42a, is changed according to the lift regulation position of the reed valve 42a, thereby reducing the inner volume of the injection port 43 downstream from the reed valve 42a.

Further, the reed valve 42a and the valve stop 42b are fixed to the intermediate pressure plate 44 by bolts 48, which are fixing members. A fixing hole for the bolt 48 provided in the valve stop 42b does not pass through the valve stop 42b and is open only on the side where the bolt 48 is inserted. Therefore, as a result, the fixing member 48 is configured to open only to the intermediate pressure chamber 41 . As a result, the working fluid can be prevented from leaking between the intermediate pressure chamber 41 and the compression chamber 15 through the gap of the fixing member 48, and the injection rate can be improved.

The volume of the intermediate pressure chamber 41 is made equal to or larger than the suction volume of the compression chamber 15 in order to supply a sufficient amount of injection to the compression chamber 15 . Here, the suction volume is the volume of the compression chamber 15 when the working fluid introduced from the suction port 17 is confined in the compression chamber 15, that is, when the suction process is completed. is the total volume of

In the scroll compressor 91 according to the present embodiment, the intermediate pressure chamber 41 is provided so as to extend over the plane of the end plate of the fixed scroll 12 to increase the volume.

However, when part of the oil 6 enclosed in the scroll compressor 91 leaves the scroll compressor 91 together with the discharged refrigerant and returns to the intermediate pressure chamber 41 from the gas-liquid separator 96 through the injection pipe 95, If too much oil 6 remains in the liquid reservoir 41b, there may be a problem that the oil 6 in the oil reservoir 20 runs short. For this reason, it is not appropriate that the volume of the intermediate pressure chamber 41 is too large. Therefore, it is preferable that the volume of the intermediate pressure chamber 41 is equal to or greater than the suction volume of the compression chamber 15 and equal to or less than 1/2 of the oil volume of the oil 6 to be enclosed.

As shown in FIG. 4, the injection port 43 is provided at a position that sequentially opens to the first compression chamber (outer compression chamber 15a) and the second compression chamber (inner compression chamber 15b). Further, the injection port 43 is located at a position where it opens to the outer compression chamber 15a during the compression stroke after the intake refrigerant is confined, as shown in (II) and (III) of FIG. 4, or ( As shown in I), it is provided through the end plate of the fixed scroll 12 at a position where it opens to the inner compression chamber 15b during the compression stroke after confining the sucked refrigerant.

In this embodiment, the oil supply path is used as the communication path between the compression chamber and the back pressure chamber, but the same effect can be obtained by providing an independent path in addition to the oil supply path. Further, the back pressure chamber is not limited to the back side of the orbiting scroll, but may be provided on the back side of the fixed scroll so that the fixed scroll is pressed against the orbiting scroll. Further, in the present embodiment, a scroll compressor having an injection pipe was used for explanation, but a scroll compressor without an injection pipe may be used.

The scroll compressor of the present disclosure is useful for a cooling and heating air conditioner, a refrigerating device such as a refrigerator, or a heat pump type hot water supply device.

1 Airtight Container 2 Compression Mechanism 3 Motor Section 4 Shaft 4a Eccentric Shaft Section 6 Oil 11 Main Bearing Member 12 Fixed Scroll 12a Recess 13 Orbiting Scroll 13a Passage 13c Wrap Tip 13e Back 14 Rotation Restraining Mechanism 15 Compression Chamber 15a Outer Compression Chamber 15b, 15b -1, 15b-2 inner compression chamber 16 suction pipe 17 suction port 18 discharge port 19 discharge reed valve 20 oil reservoir 21, 21a, 21b discharge bypass port 22 discharge pipe 25 pump 26 oil supply hole 29 back pressure chamber 30 high pressure region 31 Discharge chamber 41 Intermediate pressure chamber 41a Intermediate pressure chamber inlet 41b Liquid reservoir 42 Check valve 42a Reed valve 42b Valve stop 43 Injection port 43a Injection port inlet 44 Intermediate pressure plate (intermediate pressure chamber partition member)
45 intermediate pressure cover (intermediate pressure chamber partition member)
48 bolt (fixing member)
55 Oil supply path 55-1 Connection path 55-1a The other open end (high pressure area side)
55-1b One open end (back pressure chamber side)
55-2 Supply path 55-2a Other open end (back pressure chamber side)
55-2b One open end (compression chamber side)
66 Bearing portion 78 Seal member 91 Scroll compressor 92 Condenser 93 Evaporator 94, 94a, 94b Pressure reducer 95 Injection pipe 96 Gas-liquid separator

Claims (3)

a fixed scroll having a first end plate and a first spiral wrap;
an orbiting scroll having a second end plate and a second spiral wrap;
a compression chamber configured by meshing the fixed scroll and the orbiting scroll;
a back pressure chamber that holds back pressure that presses the orbiting scroll against the fixed scroll;
The compression chamber has an outer compression chamber positioned outside the second spiral wrap of the orbiting scroll and an inner compression chamber positioned inside the second spiral wrap of the orbiting scroll. ,
The back pressure chamber communicates only with the inner compression chamber during compression,
each of the outer compression chamber and the inner compression chamber has a suction confinement volume at the time when confinement of the working fluid is completed;
The suction containment volume of the outer compression chamber is larger than the suction containment volume of the inner compression chamber,
During compression, the inner compression chamber and the back pressure chamber communicate with each other,
A ratio of the suction confinement volume of the inner compression chamber to the volume of the inner compression chamber when the communication between the inner compression chamber and the back pressure chamber is terminated is defined as a back pressure chamber closed volume ratio,
When the internal pressure of each of the outer compression chamber and the inner compression chamber rises to a discharge pressure or higher and the ratio of the suction confinement volume to the volume of the working fluid that can be discharged to the discharge path is defined as a dischargeable volume ratio,
The scroll compressor, wherein the closed volume ratio of the back pressure chamber is smaller than the dischargeable volume ratio of the inner compression chamber and larger than the dischargeable volume ratio of the outer compression chamber. a discharge chamber from which the working fluid that has reached the discharge pressure is discharged;
a discharge port provided in the central portion of the fixed scroll;
a discharge bypass port provided in the outer compression chamber and connecting the outer compression chamber and the discharge chamber prior to the discharge port,
2. The scroll compressor according to claim 1, wherein the discharge bypass port makes the dischargeable volume ratio of the outer compression chamber smaller than the dischargeable volume ratio of the inner compression chamber. The back pressure chamber when the communication between the back pressure chamber and the inner compression chamber ends,
3. The scroll compressor according to claim 1, wherein said back pressure chamber is a closed space separated from other spaces having a pressure difference.

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