KR100942629B1 - Scroll compressor and freezing cycle using the same - Google Patents

Abstract

An object of the present invention is to reliably inject a refrigerant into the compression chamber in a gas injection cycle to improve the performance of the compressor.

The scroll compressor 40 includes a fixed scroll 7 provided with a spiral wrap 7b standing up on the hard plate 7a, a swing scroll 8 provided to be pivotable to face the fixed scroll, and a rear scroll wheel. The back pressure chamber 18 which becomes an intermediate pressure of a discharge pressure and a suction pressure is provided. In the revolving scroll, a spiral wrap 8b is placed on the hard plate 8a. A plurality of compression chambers 13 are formed between the wrap of the fixed scroll and the wrap of the swing scroll. The back pressure chamber is provided with a pipe 1 for injecting a gaseous refrigerant.

Scroll Compressor, Hard Plate, Fixed Scroll, Slewing Scroll, Back Pressure Chamber, Pipe

Description

SCROLL COMPRESSOR AND FREEZING CYCLE USING THE SAME}

The present invention relates to scroll compressors, and in particular to scroll compressors suitable for refrigeration cycles.

In order to improve the performance of a refrigeration cycle, Patent Document 1 describes the use of a gas injection cycle. As described in this publication, in a refrigeration cycle using a gas injection cycle, two pressure reducing devices are disposed in the pressure reducing unit, and a gas-liquid separator is disposed between the two pressure reducing devices. Then, a gas refrigerant having an intermediate pressure (injection pressure) that does not contribute to the endothermic ability generated in the evaporation process is taken out from the gas-liquid separator, and the extracted gas refrigerant is injected (injected) into the compression chamber of the compressor. Since the refrigerant introduced to the compressor is compressed from the intermediate pressure, the workload of the compressor is reduced. As a result, the performance of the refrigerating cycle can be improved, and the pressure loss in the evaporator is reduced because the injection gas does not pass through the evaporator.

There are various methods for gas injection, but in the scroll compressor described in Patent Document 1, one injection port is provided in a fixed scroll to inject a refrigerant. In addition, the injection port is positioned so that the gas refrigerant can be sequentially and intermittently supplied to two compression chambers having different closed volumes, and the supply time is relatively long. At this time, the injection port position is set so that the injected gas refrigerant does not flow out to the suction side, and if only one injection port is provided, the gas refrigerant can be surely injected into the compression chamber.

Another example of refrigerant injection is described in Patent Document 2. In the scroll compressor described in this publication, a liquid refrigerant is injected into the back pressure chamber instead of gas injection. Since a liquid refrigerant having a low temperature is guided from the back pressure chamber to the compression chamber, an increase in the discharge temperature is suppressed, and as a result, a temperature rise such as a winding of the motor, lubricating oil, or the like can be suppressed. Here, since it injected into the back pressure chamber instead of directly injecting into a compression chamber, even when the ratio of suction pressure and discharge pressure is large, the force which presses a turning scroll by a fixed scroll is ensured.

[Patent Document 1] Japanese Unexamined Patent Publication No. 2003-120555

[Patent Document 2] Japanese Patent Application Laid-Open No. 5-26188

In the scroll compressor, the pressure in the compression chamber changes with the swinging motion of the swinging scroll. In the scroll compressor described in Patent Document 1, since there is only one injection port, the injection amount may be extremely lowered due to pressure fluctuations in the compression chamber depending on the phase (position) of the swing scroll. In the worst case where the injection amount is lowered, the refrigerant flows back from the compression chamber to the injection port.

In addition, in a refrigeration cycle having an injection cycle, depending on the operating conditions, the refrigerant may be operated without being injected into the compressor. In this case, the injection port provided in the fixed scroll becomes a dead volume that does not contribute to compression. And when the part becomes low pressure according to the turning of the turning scroll, it re-expands and the re-expansion loss increases, and the compressor efficiency falls.

In addition, when gas refrigerant is injected into the compression chamber, the pressure in the compression chamber increases, and the force in the axial direction to separate the swing scroll and the fixed scroll from each other increases. As a result, a gap is formed between this end of the swing and fixed scroll lap and this bottom portion, and the sealability of the compression chamber is deteriorated, resulting in a decrease in the efficiency of the compressor.

In the scroll compressor described in Patent Document 2, by injecting the liquid refrigerant into the back pressure chamber, the rise in the discharge temperature can be suppressed, and the increase in the separation force between the swing scroll and the fixed scroll can be suppressed. However, in gas injection, it was possible to reduce the amount of work of the compressor by separating gas refrigerant which does not contribute to the endothermic ability, but such an effect cannot be expected in liquid injection.

Moreover, also in liquid injection, when the pressure in a compression chamber fluctuates, there exists a possibility that an injection amount may fall extremely, or a refrigerant may flow back into an injection piping through a back pressure chamber from a compression chamber. Moreover, since the differential pressure oil supply is employ | adopted in the scroll compressor of patent document 2, when injected into a back pressure chamber, the oil supply amount to sliding parts, such as a bearing, will reduce. In the differential pressure oil supply, there is no pump or the like for oil supply as described below, so it is difficult to increase the oil supply amount.

Here, in the differential pressure lubrication, the lubricating oil stored in the bottom of the sealed container of the hermetic compressor is supplied to a sliding part such as a bearing using a differential pressure between the discharge pressure and the back pressure in the back pressure chamber (back pressure). When the back pressure decreases, the lubricating oil in the atmosphere of the discharge pressure flows into the back pressure chamber through the sliding parts such as a bearing, and the back pressure is maintained. In this differential pressure oil supply, when injected into the back pressure chamber, the amount of lubricating oil flowing into the back pressure chamber is reduced, and the amount of oil supply to sliding parts such as bearings is reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of the prior art, and certainly injects refrigerant into a compression chamber and prevents backflow of the injection refrigerant. Another object of the present invention is to reliably inject a refrigerant to improve the performance of the compressor. Still another object of the present invention is to suppress the performance degradation of the compressor when no refrigerant is injected. And an object of this invention is to achieve at least one of these objects.

A feature of the present invention for achieving the above object is a scroll compressor having a back pressure chamber for pressing the swing scroll against a fixed scroll on the back side of the swing scroll, wherein the discharge pressure and suction of the scroll compressor are in the back pressure chamber. The injection pipe which injects gaseous refrigerant of the medium pressure of pressure is provided.

In this aspect, the liquid refrigerant of approximately the same pressure may be mixed into the gaseous refrigerant to be injected, and the shaft has a shaft for driving the swinging scroll, and the shaft has a through hole formed in the shaft center, and the lubricant at the lower end of the shaft. A pump may be provided to force lubrication of the sliding part of the scroll compressor.

According to another aspect of the present invention for achieving the above object, a fixed scroll provided with a spiral wrap on a hard plate, a swing scroll provided to be rotatable opposite to the fixed scroll, and a discharge pressure and a suction pressure on the back of the swing scroll. In a scroll compressor having a back pressure chamber of medium pressure, and in a swivel scroll, a spiral wrap is placed on a hard plate, and a plurality of compression chambers are formed between the lap of the fixed scroll and the lap of the swing scroll. The back pressure chamber is provided with a circuit for injecting a gaseous refrigerant.

In this aspect, the injection circuit may also inject a liquid refrigerant in addition to the gaseous refrigerant, and has an airtight container that accommodates the swing scroll and the fixed scroll, and has a pressure close to the discharge pressure at the center of the rear surface of the swing scroll. Means for forming a first space, the means for guiding the lubricating oil stored in the bottom of the sealed container to the first space, for leaking the lubricating oil from the first space into the back pressure chamber, and most of the space in the first space. Means for returning the lubricating oil to the bottom of the closed container without mixing the compressed gas in the closed container may be provided.

Further, in the above feature, a communication path is formed at this end of the outermost lap of the fixed scroll, and in accordance with the difference between the suction pressure or the compression chamber pressure and the pressure of the back pressure chamber introduced through the communication path, A back pressure regulating valve may be provided to relieve fluid in the back pressure chamber to the suction chamber or the compression chamber through a communication path to adjust the pressure of the back pressure chamber, and a back pressure hole communicating the back pressure chamber and the compression chamber or the back pressure chamber and the suction chamber may be provided. The pressure of the back pressure chamber may be adjusted by adjusting the pressure in the back pressure chamber, and a back pressure hole intermittently communicating with the back pressure chamber and the compression chamber or the back pressure chamber and the suction chamber is formed in the hard disk of the swing scroll to adjust the pressure in the back pressure chamber. You may also

Still another feature of the present invention for achieving the above object is a compressor in a refrigeration cycle in which a compressor, a switching valve, a first heat exchanger, a first pressure reducing valve, a gas-liquid separator, a second pressure reducing valve, and a second heat exchanger are sequentially connected to each other. In the back side of the revolving scroll, a back pressure chamber for pressing the revolving scroll against the fixed scroll is formed, and an injection pipe for injecting the gaseous refrigerant at an intermediate pressure between the discharge pressure and the suction pressure of the scroll compressor is provided in the back pressure chamber. It is connected to the gas-liquid separator and the injection pipe of a compressor.

According to the present invention, since the gas refrigerant or the liquid gas mixed refrigerant is reliably injected into the compressor even when the pressure in the compression chamber changes, the performance of the refrigeration cycle is improved. In addition, since the injection refrigerant does not flow back from the compression chamber, the check valve in the injection pipe is not required. In addition, the decrease in efficiency of the compressor when no refrigerant is injected can be suppressed.

EMBODIMENT OF THE INVENTION Hereinafter, one Example of the refrigeration cycle which concerns on this invention, and the scroll compressor used for it is demonstrated using drawing. 1 shows a system diagram of a refrigeration cycle 50 with an injection cycle. Figure 1 shows a refrigeration cycle 50 of the air conditioner. The air conditioner switches the cooling operation cycle and the heating operation cycle by the switching valve 41. Hereinafter, the refrigeration cycle 50 will be described for the case of cooling operation. In the cooling operation, the switching valve 41 is switched like the solid line in Fig. 1, and the coolant flows in the direction of the arrow.

The refrigeration cycle 50 includes a scroll compressor 40 for compressing the refrigerant, a switching valve 41 for switching the flow direction of the discharge gas of the scroll compressor 40, and a first heat exchanger 42 serving as a condenser. ) And the gas liquid disposed between the first and second expansion valves 43 and 45 for depressurizing the refrigerant condensed in the first heat exchanger 42, and the first and second expansion valves 43 and 45. The separator 44 and the 2nd heat exchanger 46 which evaporate the refrigerant | coolant depressurized by the 2nd expansion valve 45 are connected in order to each of these apparatuses by piping.

The injection pipe 47 is connected to the gas-liquid separator 44. One end of the injection pipe 47 is connected to the scroll compressor 40. The inside of the injection piping 47 is compressed by the compressor 40, and the gas refrigerant separated by the gas-liquid separator 44 flows from the gas-liquid mixed refrigerant condensed by the first heat exchanger 42. A check valve 48 is provided in the middle of the injection pipe 47. The compressor 40 and the first heat exchanger 42, the first pressure reducing valve 43, the gas-liquid separator 44, the injection pipe 47, and the like form an injection cycle.

The 1st heat exchanger 42 is arrange | positioned at the outdoor side, and outdoor air is ventilated by the outdoor fan which is not shown in figure, and forcibly heat exchanges with outdoor air. The first expansion valve 43 and the second expansion valve 45 expand and reduce the pressure of the refrigerant in two stages in either of the cooling and heating cycles. The 1st expansion valve 43 and the 2nd expansion valve 45 are variable in valve opening degree, and are controlled by the control apparatus which is not shown in figure.

The gas-liquid separator 44 provided between the first expansion valve 43 and the second expansion valve 45 is a liquid contained in the refrigerant expanded by the first expansion valve 43 or the second expansion valve 45. Separate the refrigerant from the gas refrigerant. Then, the liquid refrigerant is sent out to the second expansion valve 45, and the gas refrigerant is sent out to the injection pipe 47. Since the refrigerant in the gas-liquid separator 44 is expanded by the first expansion valve 43 and depressurized, it is an intermediate pressure between the discharge pressure and the suction pressure of the compressor 40. The 2nd heat exchanger 46 is a heat exchanger arrange | positioned at the indoor side, Compulsory heat exchange with indoor air by the indoor fan which is not shown in figure.

The operation of the refrigeration cycle 50 shown in the present embodiment configured as described above is described in detail below. The high temperature and high pressure gas refrigerant compressed by the scroll compressor (40) is sent to the first heat exchanger (42) through the switching valve (41), and heat exchanged with the outdoor air sent from the outdoor fan in the first heat exchanger (42). It heats and condenses and liquefies. The condensed refrigerant is sent to the first expansion valve 43, and the pressure is reduced to an intermediate pressure lower than the discharge pressure of the scroll compressor 40 at the first expansion valve 43 and higher than the suction pressure of the scroll compressor 40. . Then, it becomes a humid refrigerant in two phases of gas liquid and is sent to the gas liquid separator 44. The wet refrigerant is separated into a liquid refrigerant and a gas refrigerant by the gas-liquid separator 44.

The gas refrigerant separated by the gas-liquid separator 44 is injected into the back pressure chamber of the scroll compressor 40 to be described later through the injection pipe 47 and the check valve 48. In the scroll compressor 40, it flows into a compression chamber from a back pressure chamber. Therefore, in the cooling operation cycle, since the gas refrigerant separated by the gas-liquid separator 44 is compressed from the intermediate pressure in the compressor 40, the work load of the scroll compressor 40 is reduced, and the efficiency of the refrigeration cycle can be improved.

The reason is that even if the gas refrigerant is expanded to a low pressure and guided to the second heat exchanger 46, it does not contribute to the endothermic capacity generated in the evaporation process of the second heat exchanger 46 serving as the evaporator. This is because in the present embodiment, the latent endotherm when the liquid refrigerant evaporates and changes into a gas refrigerant is used. Therefore, only the liquid refrigerant is required for the evaporator, and no gas refrigerant is required. Therefore, the refrigerant is expanded to an intermediate pressure without expanding to a low pressure such as the suction pressure of the compressor 40, and the gasified in the state is guided to the compression chamber in the middle of the compression. Since the gas refrigerant of the intermediate pressure is compressed by the compressor 40, the power for compressing the gas refrigerant from low pressure such as suction pressure to medium pressure is omitted. In addition, since the separated gas refrigerant does not pass through the second heat exchanger 46, the pressure loss in the second heat exchanger 46 can be reduced.

On the other hand, the liquid refrigerant separated by the gas-liquid separator 44 is sent to the second expansion valve 45 to further reduce the pressure, thereby becoming a wet refrigerant of two-phase gas liquid of low temperature and low pressure. This humid refrigerant heat-exchanges and vaporizes with the indoor air which an indoor fan blows in the 2nd heat exchanger 46, and vaporizes it. As a result, it becomes a gas refrigerant and flows into the suction side of the scroll compressor 40. The gas refrigerant sent from the second heat exchanger 46 is mixed with the gas refrigerant injected into the compression chamber during compression formed in the scroll compressor 40 and compressed. Then, it is compressed to a predetermined pressure by the scroll compressor 40 and sent to the first heat exchanger 42 as a refrigerant gas of high temperature and high pressure.

The above is the operation of each device in the cooling operation cycle. In the heating operation cycle, the switching valve 41 is switched as shown by the broken line in FIG. 1, and the refrigerant flows in the opposite direction to the arrow in the figure. . In this case, the first heat exchanger 42 acts as an evaporator and the second heat exchanger 46 acts as a condenser. The refrigerant depressurized by the second pressure reducing valve 45 flows into the gas-liquid separator 44.

The detail of the scroll compressor 40 used for this injection cycle is demonstrated using FIG. 2 and FIG. Figure 2 is a longitudinal sectional view of one embodiment of a scroll compressor according to the present invention. The fixed scroll 7 is located on the outer circumferential side of the hard plate 7a formed in the shape of a disc, a wrap 7b provided in a spiral shape on the light plate 7a, and the hard plate 7a, and the wrap 7b is turned. It has the support part 7d formed in cylindrical shape so that it may become. The surface of the hard plate 7a in which the lap 7b was standing up forms this bottom 7c. The support part 7d is formed in the outer peripheral part of the fixed scroll 7, and fixes the support part 7d to the frame 17 with a bolt etc. The peripheral portion of the frame 17 fixed with the supporting portion 7d and integrated with the fixed scroll 7 is fixed to the case 9 by welding or the like.

The swinging scroll 8 which is disposed opposite the fixed scroll 7 is held in the frame 17 so as to be pivotable. The orbiting scroll 8 has a disk-shaped hard plate 8a, a spiral wrap 8b that is set up on this hard plate 8a, and a boss portion 8d provided at the back center of the hard plate 8a. . Similarly to the fixed scroll 7, the surface of the side on which the wrap 8b of the hard plate 8a is formed forms this bottom 8c. In the revolving scroll 8, the part that is on the outer diameter side than the part in which the wrap 8b is formed, and the surface in contact with the end surface of the fixed scroll 7 forms the hard plate surface 8e of the revolving scroll 8.

The case 9 is a hermetically sealed container and accommodates a scroll portion having a fixed scroll 7 and a swinging scroll 8 at the top and a motor 16 for driving the swinging scroll 8 in the lower portion. Lubricant 39 is accumulated at the bottom of the case 9. The rotor 16a of the motor 16 is attached to the shaft 10 which drives the turning scroll 8. The shaft 10 is rotatably attached to the frame 17 and coaxial with the axis of the fixed scroll 7. The crank 10a is provided in the front-end | tip part of the shaft 10, and the boss | hub part 8d of the revolving scroll 8 is rotatably attached to the crank 10a via the revolving bearing 11.

The axis of the revolving scroll 8 is eccentric with respect to the axis of the fixed scroll 7 by a predetermined distance δ. The wrap 8b of the revolving scroll 8 is overlapped with each other by moving the wrap 7b of the fixed scroll 7 by a predetermined angle in the circumferential direction. The Oldham ring 12 is mounted on the back side of the swinging scroll 8 so that the swinging scroll 8 does not rotate relative to the fixed scroll 7.

When the swing scroll 8 is pivoted by combining the wrap 8b of the swing scroll 8 and the wrap 7b of the fixed scroll 7, a plurality of compression chambers (between the two wraps 7b, 8b) 13) is formed. The compression chamber 13 has a crescent shape, and the volume is continuously reduced as the compression chamber 13 moves to the center portion. In the case of a so-called asymmetrical wrap, a plurality of compression chambers 13 are formed on the inner wall surface side and the outer wall surface side of the wrap 8b of the swinging scroll 8, respectively, in the case of a so-called asymmetric wrap, and each of the swinging inner sides It is the compression chamber 13a and the turning outer side compression chamber 13b.

The suction part 38 is formed in the outer diameter side edge part of the lap 7b of the fixed scroll 7. The suction port 14 which is a fixed hole is formed from the opposite side to the lap 7b formation surface of the fixed scroll 7. The suction port 14 guides the refrigerant from the second heat exchanger 46 to the scroll portion during the cooling operation cycle. In the suction part 38, the groove depth is gradually changed to the position corresponding to the suction port 14, and a fixing hole is formed from the lap surface so as to communicate with a part of the suction port 14 at the end thereof. The suction part 38 mitigates the change of the flow direction of the refrigerant sucked from the suction port 14.

The space formed by the wrap 7b of the fixed scroll 7 opened by the suction part 38 and the wrap 8b of the swing scroll 8 is called the suction chamber 20. The suction chamber 20 is a space in which the refrigerant from the first heat exchanger 42 is sucked from the second heat exchanger 46 in the cooling operation cycle and from the second heat exchanger 42 in the heating operation cycle. When the phase of the swinging movement of the swinging scroll 8 advances, the suction port 14 side is closed by the two scroll wraps 7b and 8b, and is switched to the compression chamber 13. In the vicinity of the vortex center of the hard plate 7a of the fixed scroll 7, a discharge port 15 is formed as a through hole. This discharge port 15 communicates with the compression chamber 13 on the innermost circumference side.

The operation of the scroll compressor of the present embodiment configured as described above will be described below. When the motor 16 drives the shaft 10 to rotate, the rotation is transmitted to the swing scroll 8 via the swing bearing 11 held by the crank portion 10a of the shaft 10. As a result, the swing scroll 8 pivots around the axis of the fixed scroll 7 at a turning radius of the distance δ. At that time, the projections formed in the Oldham ring 12 move the grooves formed on the back side of the swing scroll 8 so that the swing scroll 8 does not rotate.

As the swinging scroll 8 swings, the compression chamber 13 formed between the fixed and swinging wraps 7b and 8b continuously moves to the center. At the same time, the volume of the compression chamber 13 is continuously reduced. By the movement of the revolving scroll 8, the refrigerant sucked from the suction port 14 is sequentially compressed in each compression chamber 13. The compressed refrigerant is discharged from the discharge port 15. The refrigerant discharged from the discharge port 15 passes through the outer circumferential portion of the fixed scroll 7 in the case 9, and then the compressor 40 is discharged from the discharge pipe 6, which is a side portion of the case 9 and attached to the lower portion of the scroll portion. Is sent out to the outside, and is sent to the switching valve (41).

A volumetric or centrifugal oil supply pump 21 is attached to the lower end of the shaft 10. When the shaft 10 rotates, the oil supply pump 21 also rotates, and the lubricating oil 39 stored at the bottom of the case 9 is sucked from the lubricating oil suction port 25 formed in the oil supply pump case 22. The lubricating oil 39 sucked by the oil feed pump 21 is scroll compressor 40 through a through hole 3 extending from the discharge port 29 of the oil feed pump in the axial direction formed in the shaft portion of the shaft 10. Each part of is derived.

A part of the lubricating oil 39 guided to the upper portion is a flange-shaped swing boss member 34 provided on the frame 17 and the shaft 10, the swing scroll 8, and the boss portion 8d of the swing scroll 8. It flows into the first space 33 formed by). In the lower part of the shaft 10, a horizontal hole 24 extending in the radial direction is formed, and a part of the lubricating oil 39 is ejected from the horizontal hole 24, and the lower part of the shaft 10 is rotatably supported. After lubricating the secondary bearing 23 to be returned to the storage portion of the lubricating oil 39 at the bottom of the case 9.

In the upper part of the shaft 10 and facing the main bearing 5, a horizontal hole 4 extending in the radial direction is formed, and a part of the lubricating oil 39 is ejected from the horizontal hole 4. Lubricate the bearing (5). The lubricating oil 39 lubricating the main bearing 5 flows into the first space 33. The lubricating oil 39 reaching the upper part of the crank 10a of the shaft 10 through the through hole 3 extending up and down lubricates the turning bearing 11 and then flows into the first space 33. Here, in the shaft 10, the oil supply grooves 27 and 28 which are wide enough groove width from the bearing clearance of the bearings 5 and 11 are formed. Since the width of the lubrication grooves 27 and 28 is wide, the flow path resistance when the lubricating oil 39 passes through the main bearing 5 and the slewing bearing 11 is small, so that the upper end portions of the bearings 5 and 11 and There is almost no pressure gradient at the bottom. Therefore, the refrigerant melted in the lubricating oil 39 can be prevented from foaming under reduced pressure, and high bearing reliability is obtained.

Most of the lubricating oil introduced into the first space 33 falls to the bottom of the case 9 through the oil drain hole 26a and the oil drain pipe 26b formed in the frame 17. At this time, since the outlet position of the exhaust pipe 26b is close to the inner wall surface of the case 9 and the outlet position is formed so that the lubricant oil 39 flows downward, the lubricant oil 39 is mixed with the discharge gas and discharged out of the apparatus. Suppress what happens. As a result, it is possible to prevent the lubricating oil 39 in the compression chamber 13 from being extremely reduced to impair the reliability of the compressor 40.

Among the remaining lubricating oils 39 introduced into the first space 33, the minimum lubricating oil necessary for lubricating the Oldham ring 12 and the compression chamber 13 and sealing the compression chamber 13 is the main bearing 5. It flows into the back pressure chamber 18 from the oil leaking means provided between the upper end surface of the sealing member 32 located upward and the end surface of the turning boss member 34. As shown in FIG. Here, the back pressure chamber 18 is a space formed between the back side of the revolving scroll 8 and the frame 17.

By the way, in the scroll compressor 40, when the fixed scroll 7 and the revolving scroll 8 are arrange | positioned, and the revolving scroll 8 turns, the plurality of turns formed between the revolving and fixed laps 7b and 8b will be provided. The volume of the compression chamber 13 of sequentially decreases. Due to the compression action in the scroll compressor 40, the fixed scroll 7 and the swinging scroll 8 generate an axial force (hereinafter, referred to as a separation force) to be spaced apart from each other. When the fixed, turning both scrolls 7, 8 are spaced apart, this end of the lap 7b of the fixed scroll 7 and this bottom of the turning scroll 8, and the teeth of the lap 8b of the turning scroll 8 A gap arises between an end and this bottom of the fixed scroll 7, and the sealing property of the compression chamber 13 deteriorates, and the efficiency of a compressor falls.

Therefore, the back pressure chamber 18 which becomes a pressure (intermediate pressure) between the discharge pressure and the suction pressure of the compressor 40 is formed in the back side of the hard board 8a of the revolving scroll 8. When the intermediate pressure is acted as the back pressure of the swing scroll 8, the swing scroll 8 is pushed toward the fixed scroll 7 side to cancel the separation force. At the same time, a pulling force occurs between the turning scroll 8 and the fixed scroll 7.

However, when the pulling force is too large, the thrust force acting between the turning scroll 8 and the fixed scroll 7 becomes large, and the sliding friction between this end of both wraps 7b and 8b and this bottom is increased. Therefore, the pulling force is adjusted to an appropriate size. In order to adjust this pulling force, ie, the magnitude of the back pressure, a back pressure hole 35 was formed in the hard plate 8a of the swing scroll 8 as shown in FIG.

The back pressure hole 35 is a communication path which communicates the back pressure chamber 18 and the compression chamber 13. When the back pressure increases, the fluid in the back pressure chamber 18 is automatically released to the compression chamber 13 in accordance with the pressure difference between the back pressure chamber 18 and the compression chamber 13, so that the back pressure is maintained at an appropriate value. On the contrary, when the back pressure decreases, the fluid in the compression chamber 13 flows into the back pressure chamber 18 to increase the back pressure, thereby maintaining the back pressure at an appropriate value.

The sealing member 32 is ring-shaped, and is inserted in the round ring groove 31 formed in the frame 17 together with the wavy spring which is not shown in figure. The sealing member 32 partitions the 1st space 33 which is the discharge pressure of the compressor 40, and the back pressure chamber 18 which is an intermediate pressure of the suction pressure and discharge pressure of the compressor 40. As shown in FIG. As the oil leaking means, a plurality of holes 30 are formed in the pivot boss member 34 extending in the axial direction. When the turning scroll 8 pivots, the plurality of holes 30 move circumferentially with the sealing member 32 interposed therebetween, and the openings alternately in the first space 33 and the back pressure chamber 18. Avoid. As a result, the lubricating oil 39 in the first space 33 is transferred to the back pressure chamber 18.

The oil supply amount to the back pressure chamber 18 can be freely adjusted by changing the number of the plurality of holes 30 formed in the turning boss member 34 and the diameter and depth of each hole 30. When the back pressure rises, the lubricating oil 39 introduced into the back pressure chamber 18 flows into the compression chamber 13 through the back pressure hole 35 formed in the hard plate 8a of the swing scroll 8. And with the turning of the turning scroll 8, it moves to the center part of the turning scroll 8, and is discharged from the discharge port 15. FIG. A part of the lubricating oil 39 discharged from the discharge port 15 flows out of the apparatus from the discharge pipe 6. The remaining lubricating oil 39 is separated from the refrigerant and stored in the bottom of the case 9.

The position of the back pressure hole 35 mentioned above is set as follows. The back pressure hole 35 is formed in the hard plate 8a of the revolving scroll 8. At that time, the back pressure hole 35 is positioned so that the pressure in the back pressure hole 35 of the compression chamber 13 formed along with the swing of the swing scroll 8 becomes a value close to a predetermined back pressure value. 3 shows an example of the back pressure hole 35. The pressure in the back pressure hole 35 of the compression chamber 13 is the pressure of the turning outer line side compression chamber 13b.

Since the pressure in the swing outer side compression chamber 13b fluctuates while the swing scroll 8 makes one turn, the average pressure in one turn turns into the pressure of the back pressure hole 35 of the compression chamber 13. 4 shows the relationship between the swing angle of the swing scroll 8 and the pressure in the compression chamber 13. The horizontal axis is the crank angle corresponding to the swing angle of the swing scroll 8. As the swinging scroll 8 swings, the pressure in the swinging outer side compression chamber 13b rises from the suction pressure to the discharge pressure as shown in the line A-B-C in the figure. On the other hand, the pressure of the turning inner side compression chamber 13a rises like the line A-D-E-C in a figure.

At this time, since the position of the compression chamber 13 moves to the center with turning of the revolving scroll 8, the back pressure hole 35 may not be contained in the compression chamber 13 also. Therefore, only when the compression chamber 13 includes the back pressure hole 35, that is, only in the opening section, the pressure of the line F-G, which is the pressure of the swing outer side compression chamber 13b, acts on the back pressure hole 35. The back pressure hole 35 is formed so that the average pressure of the line F-G is balanced with the back pressure acting on the back pressure chamber 18.

Since the pressure on the compression chamber 13 side of the back pressure hole 35 fluctuates like the line FG as described above, the direction in which the coolant flows is back pressure in any crank angle range during the turning of the turning scroll 8. The chamber 18 is changed from the compression chamber 13 to the back pressure chamber 18 in the compression chamber 13 and in an arbitrary crank angle range. The flow of the refrigerant reciprocating through the back pressure hole 35 generates so-called breathing loss. Therefore, in order to reduce this respiration loss, the back pressure hole 35 is intermittently connected to the back pressure chamber 18 and the compression chamber 13.

An example in which the back pressure hole 35 communicates with the back pressure chamber and the compression chamber intermittently will be described with reference to FIGS. 5 and 6. FIG. 5 is an enlarged longitudinal sectional view of the portion around the back pressure hole 35 with respect to the scroll compressor 40 shown in FIG. 6 is a cross sectional view at the bottom plate 8a which is the bottom surface of the revolving scroll 8, showing only the fixed scroll 7 and the revolving scroll 8. A back pressure hole 35 formed in a substantially U-shaped cross section in the hard plate 8a of the revolving scroll 8, and formed on the surface of the wrap 7b side of the fixed scroll 7 and extending obliquely from the radially outer side to the inner diameter side. It also shows the communication groove 36 to be.

The communication groove 36 constitutes a part of the back pressure chamber 18. When the revolving scroll 8 rotates once, the opening 35a on the back pressure chamber 18 side of the back pressure hole 35 follows the trajectory shown by a circle 37 in FIG. At this time, the back pressure chamber 18 and the compression chamber 13 communicate only with an arbitrary crank angle range in one revolution, specifically, while the opening 35a of the back pressure hole 35 faces the communication groove 36. . In another range of the crank angle, the opening 35a of the back pressure hole 35 is closed on the surface 7e on the wrap 7b side of the fixed scroll 7, and the back pressure chamber 18 and the compression chamber 13 are closed. ) Is blocked. Since the back pressure chamber 18 and the compression chamber 13 are intermittently connected, the length of the line F-G in the compression curve shown in FIG. 4 becomes short, and the pressure fluctuation can be suppressed.

Next, the structure as the compressor 40 used for an injection cycle is demonstrated using FIG. The injection pipe 1 is provided through the case 9 so as to communicate with the back pressure chamber 18. The end of the injection pipe 1 is connected to the injection pipe 47 shown in FIG.

In the scroll compressor 40 configured as described above, the gas refrigerant separated by the gas-liquid separator 44 is injected into the back pressure chamber 18. The injected gas refrigerant, along with the lubricating oil which has reached the back pressure chamber 18 through the lubricating oil reservoir, that is, the lubricating oil reservoir at the bottom of the case 9, through the inside of the shaft 10, is compressed through the back pressure hole 35. Flows into (13). As mentioned above, since the back pressure hole 35 was intermittently connected to the back pressure chamber 18 and the compression chamber 13, the pressure fluctuation on the side of the compression chamber 13 which is the source of the gas refrigerant from the back pressure chamber 18 was carried out. Becomes smaller and the breathing loss becomes smaller. As a result, compared with the case where the gas refrigerant is directly injected into the compression chamber 13, the respiration loss can be reduced and the injection amount can be increased.

When the injection amount of the gas refrigerant is increased, the power for compressing the gas refrigerant that does not contribute to the endothermic ability in the evaporator from low pressure to medium pressure can be further reduced. Conventionally, it is difficult to inject all the separated gas refrigerants due to respiration loss or pressure loss due to flow path resistance, and some gas refrigerants have been compressed through an evaporator. In this embodiment, since the injection amount is increased, such unnecessary compression can be avoided.

Since the gas refrigerant separated by the gas-liquid separator 44 does not pass through the second heat exchanger 46, the pressure loss in the second heat exchanger 46 can be reduced. Moreover, since the influence of the pressure fluctuation on the side of the compression chamber 13 which is the source of the gas refrigerant is suppressed small, it is possible to set the injection pressure to a pressure higher than the maximum pressure of the source of the gas refrigerant. As a result, the back flow of the gas refrigerant from the compression chamber 13 through the back pressure chamber 18 to the injection pipe 47 can be prevented, and the check valve 48 serving as a noise source during the injection cycle is unnecessary.

In the conventional method of directly injecting the refrigerant gas into the compression chamber 13, the pressure of the compression chamber 13 is increased by the injection of the refrigerant gas, and the scroll scroll 8 is fixedly scrolled as compared with the case where no injection is performed. The separation force separated from (7) increases, and there exists a possibility that the efficiency of a compressor may fall.

On the contrary, according to the present embodiment, the gas refrigerant flows into the back pressure chamber 18 and the pressure loss when passing through the back pressure hole 35 causes the pressure of the gas refrigerant to decrease slightly. 13) flows into. As a result, since the separation force increases and the pressing force also increases, it is possible to prevent the efficiency of the compressor 40 from being separated by the fixed and swinging scrolls 7 and 8 being spaced apart.

In addition, in the conventional method of directly injecting into the compression chamber 13, the space on the compression chamber 13 side formed by the injection port and the check valve becomes a dead volume which does not contribute to compression when operating without injection, There was a fear of causing re-expansion loss. According to this embodiment, since no injection port is required, no dead volume is generated, and the efficiency of the compressor 40 is not lowered even when it is operated without injection. In addition, according to this embodiment, the lubricating oil 39 is supplied to the main bearing 5 and the slewing bearing 11 by the oil feed pump. Therefore, even if the refrigerant gas is injected into the back pressure chamber 18, there is no fear that the oil supply amount to the bearing sliding portion is reduced.

In the above embodiment, the gas refrigerant separated by the gas-liquid separator 44 is injected into the back pressure chamber 18, but a part of the liquid refrigerant may be injected into the back pressure chamber 18 in addition to the gas refrigerant. When the liquid refrigerant is also injected, since the low temperature liquid refrigerant flows into the compression chamber 13 via the back pressure chamber 18, the compression chamber 13 is cooled to discharge the refrigerant gas discharged from the discharge port 15. Can lower the temperature. As a result, the temperature rise of the winding of the motor, the lubricating oil, and the like can also be suppressed.

Another embodiment of the scroll compressor 40 according to the present invention will be described with reference to FIGS. 7 and 8. FIG. 7 is a longitudinal sectional view of the scroll compressor 40, and FIG. 8 is an enlarged longitudinal sectional view of the back pressure regulating valve 2 included in the scroll compressor 40. As shown in FIG. The present embodiment differs from the embodiment shown in FIG. 2 in that the oil supply to the bearing portion is a differential pressure oil supply performed by a pressure difference between the discharge pressure and the back pressure, and the back pressure is adjusted using the back pressure adjusting valve 2 instead of the back pressure hole. In tuned.

The differential pressure oil supply structure will be described. The lubricating oil 39 is stored in the lubricating oil storage part 39a of the bottom part of the case 9, and the atmospheric pressure of this lubricating oil storage part 39a is discharge pressure. On the other hand, the pressure in the back pressure chamber 18 is lower than the discharge pressure. Therefore, the lubricating oil 39 stored in the lubricating oil storage part 39a is caused by the pressure difference between the atmospheric pressure of the lubricating oil storage part 39a and the pressure of the back pressure chamber 18. It flows into the back pressure chamber 18 through the formed through hole 3.

At this time, a part of the lubricating oil 39 is opened to the part facing the main bearing 5 of the shaft 10, and the main bearing 5 through the horizontal hole 4 extending radially in the shaft 10. Lubricate the After the main bearing 5 is lubricated, the back pressure chamber 18 is reached. The remaining lubricating oil 39 reaches the upper part of the crank 10a of the shaft 10 through the through hole 3, lubricates the swivel bearing 11 and flows into the back pressure chamber 18. When the lubricating oil 39 passes through the main bearing 5 and the revolving bearing 11, the lubricating oil is tightened because the bearing gap is small, and flows into the back pressure chamber 18 at a pressure lower than the discharge pressure.

When the back pressure of the lubricating oil 39 flowing into the back pressure chamber 18 increases, the back pressure regulating valve 2 provided in the communication path to the suction chamber 20 or the compression chamber 13 opens. Since the back pressure regulating valve 2 is opened, the lubricating oil 39 flows from the back pressure chamber 18 into the suction chamber 20 or the compression chamber 13 and is discharged from the discharge port 15 through the compression chamber 13. do.

Next, the structure and operation | movement of the back pressure regulating valve 2 are demonstrated. On the outside of the wrap 7b of the fixed scroll 7, a stepped hole extending in the axial direction is formed from the rear side so as to accommodate the valve member 2a of the back pressure regulating valve 2. On the other hand, the hole is formed from the back pressure chamber 18 side in the position corresponding to this stepped hole. The hole on the back pressure chamber 18 side forms a lower space 2d communicating with the back pressure chamber 18.

A hole communicating with the stepped hole and the back pressure chamber 18 side is formed obliquely on the side of the stepped hole. The back pressure chamber 18 side edge part of the hole formed at an angle is connected to the communication path 2f which is a groove | channel formed in the surface of the wrap 7b side of the fixed scroll 7. The space 2e formed by the stepped hole and the inclined hole communicates with the suction chamber 20 or the compression chamber 13 through the communication path 2f. The valve member 2a is arrange | positioned in the upper surface of 2 d of lower spaces so that this space can be closed. The valve member 2a is urged to the lower space 2d side by a spring 2b fixed to the lower portion of the member 2c fitted into the stepped hole.

Therefore, the valve member 2a is the suction chamber 20 in which the force by the pressure of the lower space 2d which communicates with the back pressure chamber 18 was transmitted to the space 2e via the communication path 2f, or When it becomes higher than the sum total of the force by the pressure of the compression chamber 13, and the pressing force of the spring 2b, it moves upwards. And lower space 2d and space 2e are made to communicate. That is, the back pressure adjusting valve 2 reliefs the fluid in the back pressure chamber 18 to the suction chamber 20 or the compression chamber 13 when the pressure in the back pressure chamber 18 becomes higher than the preset value.

Also in the structure which has this back pressure regulating valve 2, the gas refrigerant injected into the back pressure chamber 18 via the injection piping 47 becomes with the lubricating oil which reached the back pressure chamber 18. As shown in FIG. And it flows into the suction chamber 20 or the compression chamber 13 via the back pressure regulating valve 2. Therefore, also in this embodiment, since the back pressure adjusting valve 2 intermittently communicates the back pressure chamber 18 with the suction chamber 20 or the compression chamber 13, the pressure in the back pressure chamber 18 is reduced by the suction chamber ( 20) Or, it is possible to realize a good injection that is substantially constant pressure and has low breathing loss, without being affected by the pressure fluctuation on the compression chamber 13 side.

In addition, according to the present embodiment, compared with the case of directly injecting the gas refrigerant into the compression chamber 13, respiration loss can be reduced, the injection amount can be increased, and the gas refrigerant flows back into the injection pipe 47. Since the check valve 48 is unnecessary, the gas refrigerant flows into the back pressure chamber 18, passes through the back pressure regulating valve 2, and there is a pressure loss at that time, the implementation shown in FIG. For the same reason, since the pressing force is increased along with the separation force between the fixed and swinging scrolls 7 and 8 to prevent a decrease in volume efficiency, and the conventionally required injection port is unnecessary, no dead volume is generated. When operating without injection, there is an effect that the efficiency of the compressor does not decrease.

In the present embodiment, since the lubricating oil 39 is supplied to the main bearing 5 and the swing bearing 11 by the differential pressure between the discharge pressure and the back pressure, the gas refrigerant flowing into the back pressure chamber 18 by injection is introduced. If the amount is large, the amount of lubricating oil flowing into the back pressure chamber 18 via the bearing is reduced by that amount. In other words, when not injected, the flow of fluid flowing out of the back pressure chamber can be regarded as the flow of lubricant from the oil reservoir of the bottom of the case, but when injected, the flow of injection gas is applied to the flow of the lubricant. . As a result, when the flow rate of the fluid from the back pressure chamber 18 is made constant, the lubricating oil amount decreases.

Therefore, the pressing force of the spring 2b of the back pressure regulating valve 2 is made small. If the pressing force of the spring 2b is small, the amount of fluid which is relief from the back pressure chamber 18 to the suction chamber 20 or the compression chamber 13 increases. The injection pressure is adjusted so that the amount of lubricating oil flowing into the back pressure chamber 18 is about the same as when not injected into the back pressure chamber 18. Thereby, the reduction of the oil supply amount to a bearing part can be avoided. The gas coolant containing not only the gas coolant but also the liquid coolant may be injected as in the embodiment shown in FIG.

1 is a system diagram of a refrigeration cycle according to the present invention.

Figure 2 is a longitudinal sectional view of one embodiment of a scroll compressor according to the present invention.

FIG. 3 is a plan view of the compression chamber formed by the swing scroll and the fixed scroll of the scroll compressor shown in FIG.

4 is a graph for explaining a change in pressure in the compression chamber of the scroll compressor shown in FIG.

Fig. 5 is a detailed longitudinal sectional view of the back pressure hole formed in the scroll compressor shown in Fig. 2;

FIG. 6 is a plan view of the back pressure hole formed in the scroll compressor shown in FIG.

7 is a longitudinal sectional view of another embodiment of a scroll compressor according to the present invention;

Fig. 8 is a longitudinal sectional view of the back pressure regulating valve of the scroll compressor shown in Fig. 2 or 7;

<Explanation of symbols for the main parts of the drawings>

1: injection pipe

2: back pressure regulating valve

7: fixed scroll

8: turning scroll

13: compression chamber

18: back pressure chamber

35: back pressure hole

40: scroll compressor

50: refrigeration cycle

Claims (11)

A scroll compressor having a back pressure chamber for pressing the swing scroll against a fixed scroll on the back side of the swing scroll. An injection pipe connected to the gas-liquid separator is connected to the back pressure chamber, The gas-liquid separator is disposed between the first expansion valve and the second expansion valve, The injection pipe is a scroll compressor, characterized in that for injecting the gaseous refrigerant of the pressure between the discharge pressure and the suction pressure of the scroll compressor to the back pressure chamber. The scroll compressor according to claim 1, wherein a liquid refrigerant of approximately the same pressure is mixed into the injected gaseous refrigerant. The shaft of claim 1, further comprising a shaft for driving the swing scroll, the shaft having a through hole formed in the shaft center, and a lubricating oil pump provided at the lower end of the shaft to lubricate the sliding portion of the scroll compressor. Scroll compressor, characterized in that. delete delete A fixed scroll provided with a spiral wrap on a hard plate, a swing scroll provided to be pivotally opposed to the fixed scroll, and a back pressure chamber provided at an intermediate pressure between the discharge pressure and the suction pressure on the back of the swing scroll; In a scroll compressor in which a spiral wrap is provided on a hard plate, and a plurality of compression chambers are formed between the wrap of the fixed scroll and the wrap of the swinging scroll, between the first expansion valve and the second expansion valve. An injection pipe connected to the gas-liquid separator disposed in the gas supply chamber is connected to the back pressure chamber, and the injection pipe includes an injection circuit for injecting a gaseous refrigerant into the back pressure chamber. A sealed container for accommodating the swinging scroll and the fixed scroll, a first space is formed at the center of the rear surface of the swinging scroll to a pressure close to the discharge pressure, and guides the lubricant oil stored in the bottom of the sealed container to the first space. Means for leaking lubricating oil from the first space into the back pressure chamber and returning the lubricating oil from the first space to the bottom of the sealed container without mixing most of the lubricating oil in the first container with compressed gas in the closed container. Characterized by a scroll compressor. The scroll compressor according to claim 6, wherein the injection circuit injects a liquid refrigerant in addition to the gaseous refrigerant. A fixed scroll provided with a spiral wrap on a hard plate, a swing scroll provided to be pivotally opposed to the fixed scroll, and a back pressure chamber provided at an intermediate pressure between the discharge pressure and the suction pressure on the back of the swing scroll; In a scroll compressor in which a spiral wrap is provided on a hard plate, and a plurality of compression chambers are formed between the wrap of the fixed scroll and the wrap of the swinging scroll, between the first expansion valve and the second expansion valve. An injection pipe connected to the gas-liquid separator disposed in the gas supply chamber is connected to the back pressure chamber, and the injection pipe includes an injection circuit for injecting a gaseous refrigerant into the back pressure chamber. A communication path is formed at this end of the outermost lap of the fixed scroll, and the fluid in the back pressure chamber is sucked through the communication path in accordance with the suction pressure or the pressure difference between the compression chamber pressure and the back pressure chamber pressure introduced through the communication path. And a back pressure regulating valve for relieving the seal or the compression chamber to adjust the pressure in the back pressure chamber. A fixed scroll provided with a spiral wrap on a hard plate, a swing scroll provided to be pivotally opposed to the fixed scroll, and a back pressure chamber provided at an intermediate pressure between the discharge pressure and the suction pressure on the back of the swing scroll; In a scroll compressor in which a spiral wrap is provided on a hard plate, and a plurality of compression chambers are formed between the wrap of the fixed scroll and the wrap of the swinging scroll, between the first expansion valve and the second expansion valve. An injection pipe connected to the gas-liquid separator disposed in the gas supply chamber is connected to the back pressure chamber, and the injection pipe includes an injection circuit for injecting a gaseous refrigerant into the back pressure chamber. And a back pressure hole communicating with the back pressure chamber and the compression chamber or the back pressure chamber and the suction chamber in a hard plate of the swinging scroll to adjust the pressure in the back pressure chamber. A fixed scroll provided with a spiral wrap on a hard plate, a swing scroll provided to be pivotally opposed to the fixed scroll, and a back pressure chamber provided at an intermediate pressure between the discharge pressure and the suction pressure on the back of the swing scroll; In a scroll compressor in which a spiral wrap is provided on a hard plate, and a plurality of compression chambers are formed between the wrap of the fixed scroll and the wrap of the swinging scroll, between the first expansion valve and the second expansion valve. An injection pipe connected to the gas-liquid separator disposed in the gas supply chamber is connected to the back pressure chamber, and the injection pipe includes an injection circuit for injecting a gaseous refrigerant into the back pressure chamber. And a back pressure hole intermittently communicating between the back pressure chamber and the compression chamber or the back pressure chamber and the suction chamber to adjust the pressure in the back pressure chamber by adjusting the pressure of the back pressure chamber. In a refrigeration cycle in which a compressor, a switching valve, a first heat exchanger, a first pressure reducing valve, a gas-liquid separator, a second pressure reducing valve, and a second heat exchanger are sequentially connected to each other, the compressor is the compressor according to claim 1, and the gas-liquid separator And an injection pipe of the compressor.

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