JP2008002285A - Scroll expander - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly efficient scroll expander for restraining lap deformation by the stress of a scroll expansion mechanism constituted in a sealed vessel. <P>SOLUTION: This scroll expander is constituted by arranging a radial suction passage 101 communicating with a suction part of a fixed scroll 12, and a radial delivery passage 103 communicating with a delivery part of the fixed scroll 12 inside an end plate of the fixed scroll 12. The suction passage 101 and the delivery passage 102 are constituted by being cut off from the inside of the sealed vessel 1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention engages the fixed scroll and the orbiting scroll where the spiral wrap rises from the end plate to form an expansion chamber between the two, and the orbiting scroll revolves along a circular orbit under the restriction of rotation by the rotation restricting mechanism. The present invention relates to a scroll expander that performs suction, expansion, and discharge by moving the expansion chamber while changing its volume.

  Conventionally, a scroll expander of this type of scroll fluid machine has an expansion mechanism and a compression mechanism arranged in a sealed container, and the expansion power recovered by the expansion mechanism by connecting the respective drive shafts is compressed by the compression mechanism. Configurations that are recovered as power are known.

  FIG. 4 is a diagram conceptually showing the fluid machine disclosed in Patent Document 1. As shown in FIG. 4, this type of fluid machine includes a compression mechanism 220 that compresses the refrigerant and an expansion mechanism 211 that expands the refrigerant in the casing 211. Furthermore, this fluid machine is composed of a compressor mechanism 220 that is a compressor, a gas cooler (condenser), an expansion mechanism portion 221 that is an expander, and an evaporator (evaporator), which are sequentially connected by a refrigerant pipe. It is configured. Therefore, the refrigerant is compressed by the compression mechanism unit 220, cooled by the gas cooler, expanded by the expansion mechanism unit 221, and circulated back to the compression mechanism unit 220 after being evaporated by the evaporator.

  When the refrigerant discharged from the compression mechanism unit 220 and the refrigerant sucked into the expansion mechanism unit 211 communicate with each other, a short circuit is generated, resulting in a decrease in performance on the refrigeration cycle. In order to prevent this, the fixed scroll 231 of the expansion mechanism section 211 is fixed to the casing 211, and the space inside the casing 211 is partitioned vertically.

The compression mechanism part 220 is arranged at the lower part of the casing 211, and the motor 250 is arranged at the center part and the expansion mechanism part 221 is arranged at the upper part. The drive shaft 260 of the motor is connected to the compression mechanism unit 220 and the expansion mechanism unit 221, and is configured such that the recovery power due to refrigerant expansion of the expansion mechanism unit 221 is recovered to the compression power of the compression mechanism unit 220. Yes.
JP 2001-107881 A

  However, in the fluid machine, it is necessary to partition the space inside the casing 211 into a space where the compression mechanism 220 is disposed and a suction space of the expansion mechanism 221, and the fixed scroll 231 is fixed to the casing 211. It was composed by. In this case, the fixed scroll 231 needs to be shrink-fitted and fixed to the casing 211 or welded to the casing 211. In order to complete the section, it is necessary to increase the shrinkage allowance or to weld the entire circumference of the fixed scroll 231. In any case, excessive stress can be generated in the fixed scroll 231. There was sex. When excessive stress is generated in the fixed scroll 231, the wrap shape of the fixed scroll 231 is deformed, and the performance of the expansion mechanism portion 221 may be significantly reduced.

  As a means for suppressing the deformation of the fixed scroll 231, there is a method of fixing the frame 233 of the expansion mechanism portion 221 and suppressing the deformation of the fixed scroll 231. In any case, the deformation of the fixed scroll 231 is completely suppressed. It is difficult.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a highly efficient scroll expander that suppresses lap deformation due to stress of a scroll expansion mechanism configured in a sealed container (casing 211). It is to be. Another object of the present invention is to facilitate the arrangement of the suction passage without using a complicated configuration even when the suction portion of the scroll expander is located at the center of the expansion mechanism.

  In order to solve the above-described conventional problems, the scroll expander of the present invention eliminates the partition between the space where the compression mechanism portion is disposed and the suction space of the expansion mechanism portion, and performs direct suction and direct discharge to the expansion mechanism portion. It is set as the structure to perform, and it is set as the structure which eliminates the stress deformation | transformation of the expansion mechanism part by shrink-fitting fixation and welding fixation which were required for the division.

  In the scroll expander of the present invention, the space inside the sealed container is not required to be divided into a space where the compression mechanism portion is disposed and a suction space of the expansion mechanism portion, and the fixed scroll is fixed by shrink fitting to the sealed container. Or, there is no need for welding and fixing to the sealed container, and stress deformation of the fixed scroll can be suppressed.

  Therefore, it is possible to suppress the performance degradation due to the deformation of the fixed scroll, and it is possible to provide a highly efficient scroll expander with little leakage loss. In the refrigeration cycle using the scroll expander of the present invention as an alternative to the expansion valve, it is possible to recover the expansion loss energy that has been wasted in the past with high efficiency, thereby realizing a refrigeration cycle with high energy consumption efficiency. be able to.

  According to a first aspect of the present invention, an expansion chamber is formed between the fixed scroll and the orbiting scroll in which a spiral wrap rises from the end plate inside the hermetically sealed container, and the orbiting scroll is controlled by the rotation restricting mechanism. In the scroll expander having an expansion mechanism that performs suction, expansion, and discharge by moving the expansion chamber while changing its volume when swung along a circular orbit, the inside of the fixed scroll end plate is A radial suction passage that communicates with the suction portion of the fixed scroll, and a radial discharge passage that communicates with the discharge portion of the fixed scroll, and the suction passage and the discharge passage are isolated from the inside of the sealed container. It is set as the structure made. As a result, the space inside the sealed container does not require a partition between the space where the compression mechanism portion is arranged and the suction space of the expansion mechanism portion, and the fixed scroll is shrink-fitted into the sealed container and is sealed and fixed. The need for welding and sealing is eliminated, stress deformation of the fixed scroll can be suppressed, leakage loss due to deformation of the scroll expander can be suppressed, and a highly efficient scroll expander can be provided. However, it is possible to design a scroll expander with a higher degree of freedom without using a complicated configuration by suppressing the positional installation restriction of the suction path that occurs because there is a suction path near the center of the fixed scroll. Become.

  The second invention is the first invention, in particular, in which an expansion mechanism is disposed in the upper part of a vertical sealed container, and a terminal member for supplying or extracting power is provided in the upper shell of the sealed container. is there. In this configuration, the terminal member disposed in the upper shell is often configured at the center of the upper shell in consideration of the pressure resistance of the upper shell. The position is not constrained by the positional interference of the terminal member, and it is possible to provide a scroll expander with high efficiency and high design freedom in combination with the effects of the first invention.

The third invention is the first invention, in particular, in which the expansion mechanism portion is arranged in the lower part of the vertical sealed container. In the case where the expansion mechanism is disposed at the lower part of the closed container, it is difficult to configure a suction or discharge path in the vertical direction from the lower shell of the closed container in consideration of the installation method of the expander. However, when the suction or discharge path is configured from the radial direction with respect to the fixed scroll, the effect of the first invention can be achieved even in a scroll expander in which the expansion mechanism is disposed in the lower part of the sealed container. Can fully demonstrate.

  In particular, the fourth invention is any one of the first to third inventions, and uses a high-pressure gas such as carbon dioxide as the working fluid. Since the differential pressure of carbon dioxide is larger than that of chlorofluorocarbon refrigerants, when trying to partition the space where the compression mechanism is located and the suction space of the expansion mechanism as in the background art, a stronger shrink fit Fixing and stronger welding fixing are required. Therefore, the effect of any one of the first to third inventions can be realized at a higher level. In addition, when carbon dioxide is used as the working fluid, the theoretical recovery power of the scroll expander becomes very large due to its physical properties, and in the refrigeration cycle using the scroll expander of the present invention as an alternative to the expansion valve, expansion that has been wasted in the past. Loss energy can be recovered with high efficiency, and a refrigeration cycle with high energy consumption efficiency can be realized.

  The fifth invention is, in particular, any one of the first to fourth inventions, in which the suction pipe and the discharge pipe are arranged at substantially opposite positions. According to this, the connection piping from the refrigeration cycle to the scroll expander becomes a connection at a portion closest to the farthest position on the outer periphery of the sealed container, and the vibration of the sealed container itself can be effectively reduced. In addition, when the working fluid is carbon dioxide, the scroll expander is often operated in a state where the suction state of the scroll expander is close to the supercritical liquid state. Tend to increase. In such a state, particularly when the suction and discharge pipes are connected to positions facing the sealed container, the scroll expander itself has a large vibration suppressing effect, and provides a low-noise and low-vibration high-efficiency scroll expander. can do.

  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)
FIG. 1 is a cross-sectional view of the scroll expander according to the first embodiment of the present invention. An orbiting scroll 13 that meshes with the fixed scroll 12 between the main bearing member 11 of the crankshaft 4 fixed by welding or shrink fitting in the sealed container 1 and the fixed scroll 12 bolted on the main bearing member 11. A scroll-type expansion mechanism 2 is formed by sandwiching a rotary scroll mechanism 13, and an anti-rotation mechanism 14 such as an Oldham ring that guides the orbiting scroll 13 to rotate in a circular orbit between the orbiting scroll 13 and the main bearing member 11. Is provided, and the orbiting scroll 13 is eccentrically driven by the eccentric shaft portion 4 a at the upper end of the crankshaft 4, thereby causing the orbiting scroll 13 to move circularly. Thus, the working fluid is expanded by utilizing the fact that the expansion chamber 15 formed between the fixed scroll 12 and the orbiting scroll 13 increases in volume while moving from the central portion to the outer peripheral side. In addition, this kind of scroll expander comprises a refrigerating-cycle apparatus with a compressor, a heat radiator, and an evaporator. A pressure equalizing pipe 107 is arranged at the upper part of the closed container 1 and the pressure equalizing pipe 107 is connected to a pipe so that a discharge pressure which is a high pressure of a compressor constituting a refrigeration cycle acts together with a scroll expander ( Not shown). FIG. 2 is an enlarged view of a main part of the scroll expander according to the first embodiment of the present invention. As shown in FIG. 2, a radial suction passage 101 communicating with the suction port 17 serving as a suction portion and a radial discharge passage 103 communicating with the discharge portion 102 are provided inside the fixed scroll end plate 12 a of the fixed scroll 12. Yes. A seal member 104 such as an O-ring is provided in each of the suction passage 101 and the discharge passage 102, and the suction pipe 105 and the discharge pipe 106 are inserted in a state of being shut off from the inside of the sealed container 1, respectively. When the expansion mechanism 2 in the hermetic container 1 is to perform expansion work normally, the suction passage 101 and the discharge passage 102 must be completely blocked. In this embodiment, the fixed scroll 12 is used. This is completed relatively easily.

  The working fluid is sucked from the central portion of the fixed scroll 12 through the suction pipe 105 and the suction passage 101 and shifts to the expansion stroke, and the working fluid having a predetermined pressure or less is discharged to the discharge passage 103 and the discharge pipe 106 on the outer peripheral side of the fixed scroll 12. Then, it is discharged out of the sealed container 1.

The power generated by the expansion of the working fluid is converted as electric power by the generator 3 disposed at the lower part of the expansion mechanism 2. In this embodiment, the generator 3 is used. However, if another compression mechanism is connected to the crankshaft 4, the power generated by the expansion can be used as it is as an assist for the compression mechanism. (Not shown)
The other end side of the crankshaft 4 is supported by the auxiliary bearing member 21, and a pump 25 is provided at the tip end of the other end side of the crankshaft 4. Lubricating oil is supplied from an oil reservoir 20 by a pump 25 and lubricates the main bearing portion 11a and the eccentric bearing portion 11b through an oil supply path (not shown) provided in the center of the crankshaft 4 in the axial direction. After cooling, recirculate.

  When this type of scroll expander is used, it is no longer necessary to divide the space inside the sealed container 1 into a space where the high discharge pressure of the compressor acts and a suction space of the expansion mechanism 2. It is not necessary to shrink-fit and seal and fix the sealed container 1 or weld and seal with the sealed container 1, and the stress deformation of the fixed scroll 2 can be suppressed. Therefore, it becomes possible to suppress the performance degradation due to the increase in the leakage gap due to the deformation of the fixed scroll 2, and it is possible to provide a highly efficient scroll expander with little leakage loss.

  As shown in FIG. 1, when the upper shell 108 is provided with a terminal member 109 for taking out electric power, the upper shell 108 has a problem of pressure strength of the upper shell 108 or the assembling property of the terminal member 109. In many cases, it is configured at the center of 108. In the prior art, when the expansion mechanism 2 is arranged at the upper part of the sealed container 1, the space inside the sealed container 1 is divided into a space in which a high-pressure discharge pressure of the compressor acts and a suction space of the expansion mechanism 2. Thus, interference between the terminal member 109 and the suction pipe from the outside of the sealed container 1 is avoided. When the sealed compartment is not used, it is necessary to install a suction pipe that communicates with the suction port 17 in the center portion of the fixed scroll 12 while avoiding interference with the terminal member 109. However, in the scroll expander of the embodiment, even when the upper shell 108 is provided with the terminal member 109 for taking out electric power, the connection of the suction pipe 105 in the fixed scroll 12 without using any special means. Therefore, it is possible to provide a scroll expander with high efficiency and high design freedom in combination with the effects of the first invention. Here, the terminal member 109 is used for power extraction. However, in an expander-integrated compressor in which the expansion mechanism 2 and the compression mechanism are incorporated in the sealed container 1, the terminal member 109 drives the compression mechanism. It may be a terminal member for supplying power to the motor.

  Moreover, when the expansion mechanism 2 is arrange | positioned at the lower part of the airtight container 1 like the conceptual diagram of another embodiment as shown in FIG. 3, when the installation method of a scroll expander is considered, the airtight container 1 is considered. It is difficult to insert the suction pipe 105 or the discharge pipe 106 from the lower shell 109 in the vertical direction. However, when the suction passage 101 or the discharge passage 102 is configured from the radial direction with respect to the fixed scroll 12, the scroll expander in which the expansion mechanism 2 is disposed at the lower portion of the hermetic container 1 is very simple. It is possible to provide a scroll expander that can be configured and can exhibit superior performance at low cost.

In the above embodiment, the working fluid is not particularly defined. However, when carbon dioxide, which is a high-pressure refrigerant, is used as the working fluid, the pressure difference is larger than that of the chlorofluorocarbon refrigerant. Thus, when trying to partition the space in which the compression mechanism portion is disposed and the suction space of the expansion mechanism portion, stronger shrink fitting fixing or stronger welding fixing is required. Therefore, the effect of the present invention can be realized at a higher level. Also, the theoretical recovery power of the scroll expander becomes very large due to physical properties, and in the refrigeration cycle using the scroll expander of the present invention as an alternative to the expansion valve, the expansion loss energy that has been wasted in the past is recovered with high efficiency. In addition, a refrigeration cycle with high energy consumption efficiency can be realized.

  In the present embodiment, the suction pipe 105 and the discharge pipe 106 are installed at positions facing each other as shown in FIG. 1, so that the connection pipe from the refrigeration cycle to the scroll expander is farthest from the outer periphery of the hermetic container 1. The connection is close to the position where it is. As a result, it is possible to effectively reduce the vibration of the sealed container 1 itself and to realize a scroll expander with low vibration. Furthermore, when the working fluid is carbon dioxide, the suction state is often operated in a state close to the liquid state in the supercritical state, and the scroll expander itself tends to increase in vibration due to confinement when the liquid state working fluid is inhaled. Is seen. Under these conditions, in particular, the suction and discharge pipes connected to the position facing the sealed container 1 has a great effect of suppressing the vibration of the scroll expander itself, and is a low-noise and low-vibration high-efficiency scroll. An expander can be provided. Furthermore, in this configuration, the arrangement relationship between the suction pipe 105 having a relatively high temperature and the discharge pipe 106 that is in a low temperature state after expansion can be configured to be the farthest among the fixed scrolls 12. The heat inflow from the pipe 105 to the discharge pipe 106 can be minimized, and as a result, a decrease in the evaporation capability in the evaporator connected to the discharge pipe 106 can be suppressed.

  As described above, the scroll expander according to the present invention can achieve high efficiency, low vibration, and low cost without unnecessary deformation of the fixed scroll. In addition, the working fluid is not limited to a refrigerant, and can be applied to a scroll expander that uses air or helium as a working fluid, and can be applied to a wide range of refrigeration cycle-related products such as a water heater, air conditioning, and cooling.

The longitudinal cross-sectional view of the scroll expander in embodiment of this invention Sectional drawing of the principal part of the scroll expander in embodiment of this invention The conceptual diagram of the scroll expander in another embodiment of this invention Conceptual diagram of a conventional scroll expander

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Airtight container 2 Expansion mechanism 12 Fixed scroll 12a Fixed scroll end plate 13 Orbiting scroll 14 Rotation-control mechanism 15 Expansion chamber 101 Intake passage 103 Discharge passage 109 Terminal member

Claims (5)

Inside the sealed container, a fixed scroll and a turning scroll where a spiral wrap rises from the end plate are meshed to form an expansion chamber between the two, and the turning scroll is made into a circular orbit under the restriction of rotation by the rotation restriction mechanism. In the scroll expander provided with an expansion mechanism that performs suction, expansion, and discharge by moving the expansion chamber while changing the volume when swung along, the suction of the fixed scroll inside the end plate of the fixed scroll A radial suction passage communicating with the discharge portion and a radial discharge passage communicating with the discharge portion of the fixed scroll; and the suction passage and the discharge passage are blocked from the inside of the sealed container. Scroll expander to do. 2. The scroll expander according to claim 1, wherein an expansion mechanism is disposed in an upper part of the vertical sealed container, and a terminal member for supplying or extracting power is provided in the upper shell of the sealed container. 2. The scroll expander according to claim 1, wherein an expansion mechanism is disposed in a lower part of the vertical sealed container. The scroll expander according to any one of claims 1 to 3, wherein the working fluid is carbon dioxide. The scroll expander according to any one of claims 1 to 4, wherein the suction pipe and the discharge pipe are disposed approximately opposite to each other.

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