JP2009002221A - Scroll expander - Google Patents

Abstract

The temperature in the closed container of the expander is lower than the temperature in the closed container of the compressor. Therefore, when the viscosity of the lubricating oil is selected from the viewpoint of ensuring the reliability of the compressor, There was a problem that the viscosity in the sealed container was increased, causing a reduction in power recovery efficiency due to an increase in viscosity loss.
A seal member 5 for partitioning a central portion and an outer peripheral portion is disposed between an anti-wrap side of a revolving scroll 13 and a main bearing member opposed thereto, and the high pressure gas or high pressure is maintained at the central portion. The scroll expansion mechanism is maintained at a low pressure or a discharge pressure at the outer periphery, and the outer periphery is maintained at a low pressure or a discharge pressure by a communication passage communicating with the discharged working fluid. At the same time, the communication passage is formed by intersecting at least two passages at an acute angle.
[Selection] Figure 1

Description

  In the present invention, the fixed scroll and the orbiting scroll in which the spiral wrap rises from the end plate are meshed to form an expansion chamber therebetween, and the orbiting scroll is revolved along a circular orbit under the restriction of rotation by the rotation restriction mechanism. The present invention relates to a scroll expander that performs suction and discharge when the expansion chamber moves while changing its volume.

  Conventionally, a fluid machine in which an expansion mechanism unit, an electric motor unit, and a compression mechanism unit are connected by a single rotating shaft is known (see, for example, Patent Document 1).

  FIG. 4 is a cross-sectional view showing a conventional fluid machine described in Patent Document 1. As shown in FIG. In FIG. 4, in the expansion mechanism section, power is generated by the expansion of the introduced fluid. The power generated in the expansion mechanism unit is transmitted to the compression mechanism unit by the rotating shaft together with the power generated in the electric motor unit. The compression mechanism unit is driven by the power transmitted from the expansion mechanism unit and the electric motor unit, and sucks and compresses the fluid.

  The rotating shaft is provided with a lubrication path for lubricating the expansion mechanism section, the compression mechanism section, and the like. The oil supply path is formed in the axial direction of the rotating shaft, and sucks the lubricating oil accumulated at the bottom of the sealed container by the centrifugal pump action. The lubrication path supplies lubricating oil to the compression mechanism unit, the expansion mechanism unit, and the like.

Furthermore, the partition part is provided in the airtight container in order to suppress that the heat of the fluid in the compression mechanism part moves to the fluid into the expansion mechanism part. The partition portion is provided with a fluid return passage communicating the expansion mechanism portion and the compression mechanism portion. The fluid return passage prevents fluid such as lubricating oil supplied to the expansion mechanism section and liquid refrigerant expanding in the expansion mechanism section from accumulating in the space on the expansion mechanism section side.
JP 2006-132329 A

  However, the lubricating oil heated by the compression mechanism is once cooled by lubricating the expansion mechanism, and then returned to the compression mechanism by the fluid return passage and heated again. Therefore, there has been a problem in that the capacity of the refrigeration cycle is reduced due to the heat in the compression mechanism section moving into the expansion mechanism section.

  In order to solve the above-described problem, a refrigeration cycle having two sealed containers, that is, a compressor in which a compression mechanism section and an electric motor section are housed in a sealed container, and an expander in which an expansion mechanism section and an electric motor section are housed in the sealed container. A device is considered. The power generated in the expander is converted into electric power by the electric motor unit and transmitted to the compressor. In this refrigeration cycle apparatus, the compressor and the expander have independent lubricating oil reservoirs and lubricating paths, and are connected by a connecting pipe that can supplement the lubricating oil only when the lubricating oil is excessive or insufficient. ing. According to this configuration, since there is no movement of the lubricating oil of the compressor and the expander during stable operation, the capacity of the refrigeration cycle is not reduced due to the heat in the compressor moving into the expander.

However, since the temperature in the closed container of the expander is lower than the temperature in the closed container of the compressor, when the viscosity of the lubricating oil is selected from the viewpoint of ensuring the reliability of the compressor, the expander is sealed. There has been a problem that the viscosity in the container is increased and the power recovery efficiency is reduced due to an increase in viscosity loss. Also, if the refrigerant as the working fluid is carbon dioxide, the inside of the expander's sealed container will be at high pressure and low temperature, the density of the refrigerant will reverse the density of the lubricant and the lubricant will accumulate at the top of the sealed container, There was a problem that the reliability could not be ensured because the lubricating oil could not be supplied to the sliding part.

  The present invention solves the above-mentioned conventional problems, and provides a scroll expander that ensures high efficiency and high reliability by preventing a decrease in the temperature in the expander hermetic container while preventing a decrease in the capacity of the refrigeration cycle. The purpose is to do.

  In order to solve the above-described conventional problems, the scroll expander according to the present invention includes a seal member that partitions the central portion and the outer peripheral portion between the anti-wrap side of the orbiting scroll and the main bearing member opposed thereto. In addition, a high-pressure gas or lubricating oil maintained at a high pressure is supplied to the central portion, and the outer peripheral portion is a scroll expansion mechanism portion maintained at a low pressure or a discharge pressure, and is a communication passage communicating with the discharged working fluid. Thus, the outer peripheral portion is maintained at a low pressure or a discharge pressure, and at least two passages intersect each other at an acute angle. As a result, it is possible to prevent the discharged liquid refrigerant from accumulating on the outer peripheral portion, and thus it is possible to prevent the temperature in the expander hermetic container from being lowered and to provide a scroll expander that ensures high efficiency and high reliability. With the goal.

  The scroll expander of the present invention can achieve high efficiency and high reliability, particularly when a carbon dioxide refrigerant is used.

  In the first aspect of the invention, a seal member for partitioning the central portion and the outer peripheral portion is disposed between the anti-wrap side of the orbiting scroll and the main bearing member opposed thereto, and the high pressure gas or high pressure is maintained in the central portion. The scroll expansion mechanism is maintained at a low pressure or discharge pressure, and the outer periphery is maintained at a low pressure or discharge pressure by a communication passage communicating with the discharged working fluid. The communication passage is formed by intersecting at least two passages at an acute angle. As a result, it is possible to prevent the discharged liquid refrigerant from accumulating on the outer peripheral portion, and therefore, it is possible to prevent a decrease in the temperature in the expander hermetic container and to provide a scroll expander that ensures high efficiency and high reliability. Can do.

  In the second invention, in particular, a heat insulating element is provided between the discharge pipe from which the working fluid is discharged out of the sealed container and the sealed container of the first invention. As a result, the effect that the sealed container is cooled by the heat transmitted from the discharge pipe can be prevented, so that a scroll expander that ensures higher efficiency and higher reliability can be provided.

  According to the third invention, in particular, the suction chamber is provided between the suction pipe through which the working fluid is sucked into the sealed container and the expansion mechanism part of the first or second invention. As a result, the working fluid in the hermetic container can be heated without degrading the capacity of the refrigeration cycle, so that a scroll expander that ensures higher efficiency and higher reliability can be provided.

  In the fourth aspect of the invention, in particular, the suction chamber is arranged in the lubricating path of the lubricating oil of the third aspect of the invention. As a result, the working fluid and the lubricating oil in the sealed container can be heated at the same time without degrading the capacity of the refrigeration cycle, so that it is possible to provide a scroll expander that ensures higher efficiency and reliability. .

In the fifth aspect of the invention, in particular, the power generation efficiency of the electric motor section of any one of the first to fourth aspects of the invention is 95% or less. As a result, the working fluid in the hermetic container can be heated by the loss that occurs when the power recovered by the expansion mechanism is converted into electric power, so the scroll expander ensures higher efficiency and higher reliability. Can be provided.

  In the sixth invention, in particular, the refrigerant as the working fluid according to any one of the first to fifth inventions is carbon dioxide. As a result, the inside of the hermetic container of the expander becomes high pressure and low temperature, and depending on the operating conditions, the density of the refrigerant reverses to the density of the lubricating oil and the lubricating oil accumulates on the upper part of the hermetic container, and the lubricating oil flows to the sliding part. In some cases, reliability cannot be ensured, but the working fluid in the sealed container can be heated without degrading the capacity of the refrigeration cycle. It is possible to provide a scroll expander that ensures higher efficiency and higher reliability.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
The refrigeration cycle equipment in which the present invention is used is a refrigeration cycle including a compressor, an expander, a condenser, and an evaporator, and a refrigerant is enclosed as a working fluid. The refrigerant compressed by the compressor is radiated by the condenser and then expanded by the expander. At this time, the power generated by the expansion process is converted into electric power by the electric motor unit and supplied to the compressor. The refrigerant expanded by the expander absorbs heat by the evaporator and is compressed by the compressor again. In an ordinary refrigeration cycle, an expansion valve is provided instead of an expander. However, the refrigeration cycle equipment in which the present invention is used recovers expansion power by using the expander, and the high efficiency of the refrigeration cycle equipment. It is planned.

  FIG. 1 shows a cross-sectional view of a scroll expander according to Embodiment 1 of the present invention. It is fixed between a main bearing member 11 that pivotally supports the main shaft portion 4a of the crankshaft 4 fixed by welding or shrink fitting in the sealed container 1, and a fixed scroll 12 bolted on the main bearing member 11. An Oldham that forms a scroll-type expansion mechanism by sandwiching the orbiting scroll 13 that engages with the scroll 12 and guides the orbiting scroll 13 to rotate between the orbiting scroll 13 and the main bearing member 11 so as to move in a circular orbit. A rotation restricting mechanism 14 such as a ring is provided.

  In the above configuration, the orbiting scroll 13 is eccentrically driven by the eccentric shaft portion 4 b at the upper end of the crankshaft 4, thereby causing the orbiting scroll 13 to move in a circular orbit, thereby forming between the fixed scroll 12 and the orbiting scroll 13. A refrigerant gas is sucked from a suction pipe 16 communicating with the outside of the hermetic container 1 and a suction port 17 in the central part of the fixed scroll 12 by using the expansion chamber 15 which is enlarged while moving from the central part to the outer peripheral side. The refrigerant gas that has been expanded and reduced to a predetermined pressure or less is repeatedly discharged from the discharge pipe 18 on the outer peripheral side of the fixed scroll 12 to the outside of the sealed container 1.

  The other end of the crankshaft 4 is supported by the auxiliary bearing member 21, and a positive displacement pump 25 is provided at the other end of the crankshaft 4. The lubricating oil 6 lubricates and cools the main bearing portion 11a and the eccentric bearing portion 11b through a lubricating oil reservoir 20 through a positive displacement pump 25 (not shown) provided in the center of the crankshaft 4 in the axial direction. After that, recirculation is performed through the lubricating oil return hole 26. A seal member 5 that partitions the central portion and the outer peripheral portion is disposed on the tip surface of the boss portion on the opposite side of the orbiting scroll 13. At this time, the seal member 5 has a role of partitioning the pressure of the lubricating oil 6 reaching the eccentric bearing portion 11 b and the pressure of the back pressure chamber 29 formed on the outer peripheral portion of the seal member 5. The center of is kept at high pressure.

Further, the inside of the sealed container 1 communicates with a compressor (not shown) through the connecting pipe 40, and the pressure in the sealed container 1 is maintained at a high pressure. When the lubricating oil 6 in the sealed container 1 is insufficient, the lubricating oil 6 of the compressor increases, and the lubricating oil 6 is supplied from the compressor to the expander through the connecting pipe 40. On the other hand, when the amount of the lubricating oil 6 in the sealed container 1 increases, the lubricating oil 6 is supplied from the expander to the compressor through the connecting pipe 40. To be supplied.

  The back pressure chamber 29 is maintained at a low pressure or a discharge pressure, and the communication passage 30 communicating with the discharged refrigerant maintains the outer peripheral portion at a low pressure or a discharge pressure. The communication passage 30 includes at least two passages. It is configured to intersect at an acute angle (not shown in the cross section of FIG. 1).

  FIG. 2 is a perspective view of the fixed scroll 12 in the scroll expander of the present embodiment. As can be seen from FIG. 2, the communication passage 30 is formed by intersecting two passages at an acute angle, one end communicating with the discharged refrigerant, and the other end communicating with the back pressure chamber 29. . Thereby, the liquid refrigerant discharged after expansion can be prevented from accumulating on the outer peripheral portion, and only the gasified refrigerant can be supplied to the back pressure chamber 29. Since the gasified refrigerant has less cooling effect on the refrigerant in the sealed container 1 and the lubricating oil 6 supplied to the central portion of the seal member 5 than the liquid refrigerant, the temperature drop in the sealed container 1 is effectively reduced. Can be prevented. Further, as shown in FIG. 1, a heat insulating element 41 is inserted between the discharge pipe 18 and the fixed scroll 12 in the sealed container 1 so that the refrigerant in the sealed container 1 is not cooled by the expanded refrigerant. It has become.

  Even when the viscosity of the lubricating oil 6 is selected from the viewpoint of ensuring the reliability of the compressor by measures for suppressing the cooling of the refrigerant and the lubricating oil 6 in the sealed container 1 as described above, the expansion machine is sealed. Since the increase in viscosity in the container 1 can be suppressed to a low level, it is possible to provide a scroll expander that can prevent a reduction in power recovery efficiency due to an increase in viscosity loss and ensure high efficiency and high reliability.

(Embodiment 2)
FIG. 3 shows a cross-sectional view of a scroll expander according to Embodiment 2 of the present invention. As shown in FIG. 3, a suction chamber 15a is formed on the surface of the fixed scroll 12 on the side opposite to the wrap, and the refrigerant gas sucked from the suction pipe 16 communicating with the outside of the hermetic container 1 flows into the suction chamber 15a and then is fixed. The refrigerant gas is sucked from the suction port 17 at the center of the scroll 12 to expand. Further, the lubricating oil 6 lubricates the main bearing portion 11a and the eccentric bearing portion 11b through the lubricating oil reservoir 20 through the positive displacement pump 25 (not shown) provided in the center of the crankshaft 4 in the axial direction. And after cooling, it passes through the lubricating oil return hole 26, passes through the lubricating oil passage 26a, once rises to the vicinity of the suction chamber 15a, and then recirculates through the lubricating oil passage 26b to the lower part of the sealed container 1. At this time, since the refrigerant cooled by the radiator has a higher temperature than the refrigerant that has undergone the expansion process by the expander, the lubricating oil 6 that has risen near the suction chamber 15a can be warmed. As a result, even when the viscosity of the lubricating oil 6 is selected from the viewpoint of ensuring the reliability of the compressor, the increase in the viscosity of the expander in the sealed container 1 can be suppressed to a lower level. It is possible to provide a scroll expander that prevents a decrease in efficiency and ensures higher efficiency and reliability.

  In addition, by setting the power generation efficiency of the electric motor unit 3 to 95% or less, the working fluid in the sealed container 1 can be heated by a loss generated when the power recovered by the expansion mechanism unit 2 is converted into electric power. Therefore, it is possible to provide a scroll expander that ensures higher efficiency and higher reliability.

When the refrigerant as the working fluid is carbon dioxide, the inside of the expander's sealed container 1 becomes high pressure / low temperature, and the density of the refrigerant is reversed to the density of the lubricating oil 6 so that the lubricating oil 6 is at the top of the sealed container. However, the lubricating oil 6 cannot be supplied to the sliding portion and reliability may not be ensured. However, the cooling of the working fluid in the sealed container 1 is suppressed without reducing the capacity of the refrigeration cycle, Or since it can heat, the scroll expander which ensured higher efficiency and high reliability can be provided.

  As described above, in the scroll expander according to the present invention, the seal member that partitions the center portion and the outer peripheral portion is disposed between the anti-wrap side of the orbiting scroll and the main bearing member facing the center portion, and the center portion A high-pressure gas or lubricating oil maintained at a high pressure is supplied to the outer peripheral portion, and the outer peripheral portion is a scroll expansion mechanism portion maintained at a low pressure or a discharge pressure, and the outer peripheral portion is formed by a communication passage communicating with the discharged working fluid. While maintaining the low pressure or the discharge pressure, the communication passage is formed by intersecting at least two passages at an acute angle. As a result, it is possible to prevent the discharged liquid refrigerant from accumulating on the outer peripheral portion, and thus it is possible to prevent the temperature in the expander hermetic container from being lowered and to provide a scroll expander that ensures high efficiency and high reliability. Therefore, the present invention can be applied to a scroll fluid machine including a scroll expander using air or helium as a working fluid, or a scroll fluid machine including a compressor, without limiting the working fluid to a refrigerant.

Sectional drawing of the scroll expander in Embodiment 1 of this invention The perspective view of the fixed scroll in Embodiment 1 of this invention Sectional drawing of the scroll expander in Embodiment 2 of this invention Sectional view showing a conventional fluid machine

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 Expansion mechanism part 3 Electric motor part 5 Seal member 6 Lubricating oil 12 Fixed scroll 13 Orbiting scroll 14 Rotation control mechanism 15 Expansion chamber 15a Suction chamber 29 Back pressure chamber 30 Communication channel 41 Heat insulation element

Claims (6)

The expansion mechanism part and the electric motor part are connected and stored in a sealed container via a crankshaft, and the expansion mechanism part is inflated between the fixed scroll and the orbiting scroll where the spiral wrap rises from the end plate. A chamber is formed, and the expansion chamber moves while changing its volume when the orbiting scroll is rotated under the rotation restriction by the rotation restriction mechanism while engaging the eccentric shaft portion connected to the crankshaft. In this manner, the working fluid is sucked and discharged, and a seal member for partitioning the central portion and the outer peripheral portion is disposed between the anti-wrap side of the orbiting scroll and the main bearing member opposed thereto. Supplying high-pressure gas or lubricating oil maintained at high pressure to the central portion, and the outer peripheral portion is a scroll expansion mechanism portion maintained at low pressure or discharge pressure,
The scroll expander is characterized in that the outer peripheral portion is maintained at a low pressure or a discharge pressure by a communication passage communicating with the discharged working fluid, and at least two passages intersect each other at an acute angle. . The scroll expander according to claim 1, wherein a heat insulating element is provided between the discharge pipe through which the working fluid is discharged to the outside of the sealed container and the sealed container. The scroll expander according to claim 1, wherein a suction chamber is provided between the suction pipe through which the working fluid is sucked into the sealed container and the expansion mechanism. The scroll expander according to claim 3, wherein a suction chamber is arranged in a lubricating path of the lubricating oil. The scroll expander according to any one of claims 1 to 4, wherein the power generation efficiency of the motor section is 95% or less. The scroll expander according to any one of claims 1 to 5, wherein the refrigerant as the working fluid is carbon dioxide.

Images