JP2008075532A - Expander - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an expander having a means capable of suppressing the occurrence of excessive expansion by a simple means when an excessive expansion which causes the lowering of a power recovery efficiency may occur in the expansion chamber of the expander. <P>SOLUTION: In this expander, an expansion chamber 11 demarcated by a cylinder 8, a rotor 9, and a vane 13 and a power recovery shaft 10 pivotally supporting the eccentric rotor 9 are installed in a casing 4a. A working fluid flowing into the expansion chamber 11 is expanded while moving from a high-pressure state to a low-pressure state. The eccentric rotor 9 and the power recovery shaft 10 connected to the eccentric rotor are rotatingly driven. An oil reservoir chamber 7 in which a lubricating oil is reserved is formed in the casing 4a. An oil path 10a having a reverse flow prevention means 15 to connect the oil reservoir chamber 7 and the expansion chamber 11 is formed in the casing. The lubricating oil is injected from the oil reservoir chamber 7 into the expansion chamber 11 through the oil path 10a according to the difference between the pressure inside the expansion chamber 11 and the pressure inside the oil reservoir chamber 7. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an expander that recovers energy by generating power by expansion of a high-pressure fluid, and more particularly relates to a configuration that prevents an overexpansion phenomenon of a high-pressure fluid that causes a reduction in energy recovery efficiency.

  The conventional refrigeration cycle is configured by sequentially connecting a compressor, a radiator, an expansion valve, and a heat absorber. The refrigerant circulating in the refrigeration cycle is compressed by a compressor to become high temperature and high pressure, cooled by a radiator, then adiabatically expanded by an expansion valve and depressurized. Subsequently, it flows into the heat absorber, absorbs ambient heat and is heated, and then returns to the compressor. This conventional refrigeration cycle is shown as a cycle that follows point A → B point → C point → D point on the Mollier diagram of FIG. 4. In the conventional expansion valve, the refrigerant is from point C to point D. Since the pressure is reduced by the isoenthalpy change indicated by the dotted line, the energy of the high-pressure working fluid cannot be used effectively. On the other hand, in a refrigeration cycle that uses an expander instead of an expansion valve, the working fluid that has been decompressed by an equal enthalpy change at the expansion valve in the conventional refrigeration cycle is decompressed by adiabatic expansion from high pressure to low pressure by the expander. However, the isentropic change indicated by the solid line from the C point to the D ′ point is shown, and the energy that can be absorbed by the heat absorber 5, that is, the energy that can be absorbed from the low heat source side of the refrigeration cycle is represented by the D point → Since it can be increased from point A to point D ′ → point A, the refrigeration cycle can be made highly efficient.

  For example, as shown in FIG. 9, the expander includes a cylinder 59 having a cylindrical inner space, and an eccentric rotor 61 that performs a revolving motion along the inner circumferential surface of the inner space of the cylinder 59. An expansion chamber 62 is formed between the eccentric rotor 61 and a vane 63 that slides up and down.

  The cylinder 59 includes an opening / closing valve 69, and an inflow port 64 for introducing a high-pressure fluid into the expansion chamber 62 and an outflow port 65 for leading out a low-pressure fluid expanded from the high-pressure fluid to the outside. The vane 63 is pressed by pressing means (not shown), and the lower end portion is always in sliding contact with the outer peripheral surface of the eccentric rotor 61 to partition the expansion side and the discharge side. It is like that. The eccentric rotor 61 is connected to the power recovery shaft 60 via a crankshaft, and the eccentric rotor 61 revolves with respect to the cylinder 59 by the action of high-pressure fluid introduced from the inflow port 64. If it does, the said power collection | recovery shaft 60 will perform a rotational motion via a crankshaft, and this rotational motion is utilized for electric power generation, such as a generator.

  As the eccentric rotor 61 revolves, the expansion chamber 62 formed in the inner space of the cylinder 59 has a portion that was on the suction / expansion side as needed, a portion that was on the discharge side, and a portion that was on the discharge side as needed. The high-pressure fluid suction / expansion action and the discharge action are simultaneously performed in parallel. During the revolving motion of the eccentric rotor 61, the angle range of the suction process in which the high-pressure fluid is supplied into the cylinder 59 and the angle range of the expansion process in which the fluid is expanded are determined in advance. The density ratio of the refrigerant and the discharged refrigerant is set to be constant. The high pressure fluid is introduced into the cylinder in the angular range of the suction process, while the fluid is expanded at a predetermined expansion ratio in the remaining angular range of the expansion process, and the rotational power is recovered. On the other hand, in a vapor compression refrigeration cycle connected to an expander, the high pressure and low pressure of the refrigeration cycle change due to the temperature change of the object to be cooled and the temperature change of the object of heat dissipation. The density of the intake refrigerant and exhaust refrigerant of the expander also varies.

  The expander is designed to obtain the maximum power recovery efficiency when it is operated at the design expansion ratio. FIG. 10 (A) shows the volume change of the expansion chamber under ideal operating conditions. It is a graph which shows the relationship between a pressure change. As shown in FIG. 10A, the high-pressure fluid is supplied into the expansion chamber from the point a to the point b, and starts to expand from the point b. When the point b is passed, the supply of the high-pressure fluid stops, so that the pressure once drops suddenly to the point c, and then gradually decreases to the point d while expanding. Then, after the cylinder volume of the expansion chamber becomes maximum at the point d, the volume is reduced on the discharge side and discharged to the point e. Thereafter, returning to the point a, the inhalation process of the next cycle is started. In the state of this figure, the pressure at the point d coincides with the low pressure of the refrigeration cycle, so that the operation with efficient power recovery is performed.

  When an expander is used in the refrigeration cycle of an air conditioner, the expansion ratio of the refrigeration cycle differs from the design expansion ratio of the expander due to changes in operating conditions such as switching between cooling operation and heating operation and changes in outside air temperature. Cases arise. If the actual expansion ratio of the refrigeration cycle becomes smaller than the design expansion ratio of the expander due to changes in operating conditions, a state occurs in which the pressure in the expansion chamber becomes lower than the low-pressure side pressure of the refrigeration cycle, so-called expansion of the expander An over-expansion phenomenon will occur in the chamber.

  FIG. 10B is a graph showing the relationship between the volume change of the expansion chamber and the pressure change when the overexpansion phenomenon occurs in the expansion chamber, and the low pressure side pressure of the refrigeration cycle is in an increased state. . In this case, after the fluid is supplied into the cylinder between the points a and b, the pressure decreases to the point d according to the design expansion ratio of the expander. On the other hand, the low pressure of the refrigeration cycle is at a point d 'higher than the point d. Therefore, after the expansion process is completed, the refrigerant is pressurized from the point d to the point d 'in the discharge process, and then discharged until the point e', so that the suction process of the next cycle is started.

  In the state shown in FIG. 10B, internal consumption of power is performed in the expander for discharging the refrigerant. That is, at the time of occurrence of overexpansion, the recovery power recovered from the expansion energy of the refrigerant can be obtained only by (area I) − (area II), and compared with the operation state shown in FIG. The recovery power will be greatly reduced. The expander is designed to obtain the maximum power recovery efficiency when the operation is performed at the designed expansion ratio. If an overexpansion phenomenon occurs, the power recovery efficiency will be greatly reduced. There was a problem.

In order to cope with the refrigerant overexpansion phenomenon, for example, as shown in FIG. 9, the outflow port 65 is connected to an intermediate position in the expansion process of the expansion chamber 62, and an opening / closing mechanism 67a and a check valve 68 are provided. A technique is proposed in which a communication passage 67 is provided so that the opening / closing mechanism 67a opens and closes according to the pressure difference between the outflow port 64 and the expansion chamber 62. When overexpansion occurs in the expansion chamber 62 and the pressure in the expansion chamber 62 becomes lower than the pressure in the outflow port 65, the opening / closing mechanism 67 a is opened, and refrigerant is supplied from the outflow port 65 to the expansion chamber 62. The pressure in the expansion chamber 62 is restored to the low pressure of the refrigerant circuit to suppress the overexpansion phenomenon. There is also a method of connecting the inflow port 64 and the expansion chamber 62 through a communication passage 66 having an opening / closing mechanism 66a. . (Refer to Patent Document 1 except that the assigned number is different.)
Therefore, in order to reduce the dead volume generated between the check valve 68 and the discharge port of the expansion chamber 62 as much as possible, the check valve 68 is provided near the discharge port of the expansion chamber 62. High-pressure refrigerant from the inflow port 64 flows into the section A indicated by the arrow between the check valve 68 and the discharge port of the expansion chamber 62, and the refrigerant that has flowed in There is a problem that the power recovery efficiency is reduced by that amount because it does not contribute to the power recovery in the chamber 62.
JP 2004-190559 A (page 7, FIG. 4)

  In view of the above problems, the present invention eliminates the so-called dead volume portion in the expansion chamber when preventing the overexpansion phenomenon in the expansion chamber, and an expander capable of performing power recovery operation with high efficiency. The purpose is to provide.

  In order to solve the above problems, the present invention includes an expansion chamber defined by a cylinder, an eccentric rotor, and a vane in a casing, and a power recovery shaft that pivotally supports the eccentric rotor, and flows into the expansion chamber. In an expander in which a working fluid expands while shifting from a high pressure state to a low pressure state and rotationally drives the eccentric rotor and a power recovery shaft connected thereto, the oil in which lubricating oil is stored in the casing A reservoir chamber is provided, and an oil passage provided with a backflow prevention means is provided to connect the oil reservoir chamber and the expansion chamber, and according to the difference between the pressure of the expansion chamber and the pressure of the oil reservoir chamber, Lubricating oil is injected into the expansion chamber from the oil reservoir chamber via the oil passage.

  According to the present invention, the casing includes an expansion chamber defined by a cylinder, an eccentric rotor, and a vane, and a power recovery shaft that pivotally supports the eccentric rotor, and the working fluid that has flowed into the expansion chamber is in a high pressure state. In an expander that expands while shifting to a low pressure state and rotationally drives the eccentric rotor and a power recovery shaft connected thereto, an oil reservoir chamber in which lubricating oil is stored is provided in the casing, and An oil passage having a backflow prevention means is provided to connect the oil reservoir chamber and the expansion chamber, and the oil reservoir chamber is configured to provide the oil passage according to a difference between the pressure of the expansion chamber and the pressure of the oil reservoir chamber. By injecting lubricating oil into the expansion chamber via a passage, when an overexpansion phenomenon occurs in the expansion chamber, the volume of the expansion chamber is reduced by the injected lubricating oil and overexpanded. Thereby making it possible to suppress the elephant. Further, even when an overexpansion phenomenon does not occur in the expansion chamber, the injection circuit such as the oil passage can be sealed with an incompressible lubricating oil, and so-called dead volume is reduced as much as possible. Can be done. Furthermore, since the lubricating oil is only in a liquid phase and hardly changes in volume due to a change in pressure, an expander capable of efficient operation can be provided.

  According to a second aspect of the invention, the oil passage is formed in the power recovery shaft and the eccentric rotor.

  According to a second aspect of the present invention, the oil passage can be easily provided without a separate member due to the structure formed in the power recovery shaft and the eccentric rotor. Yes.

  According to a third aspect of the invention, the cylinder and the eccentric rotor are immersed in the lubricating oil in the oil reservoir chamber.

  In the invention according to claim 3, the length of the oil injection hole 30 can be shortened as much as possible by the configuration in which the cylinder and the eccentric rotor are immersed in the lubricating oil in the oil reservoir chamber. In addition to being easy to process, the lubricating oil can be injected quickly in response to the overexpansion phenomenon. Further, the volume of the casing can be minimized as much as possible, and a compact expander can be obtained.

  According to a fourth aspect of the present invention, the oil passage is composed of an arc-shaped passage formed in the cylinder along the circumferential direction and a plurality of passages connecting the passage to the expansion chamber. It has become.

  According to a fourth aspect of the present invention, the oil passage is composed of an arc-shaped passage formed in the cylinder along the circumferential direction and a plurality of passages connecting the passage to the expansion chamber. Thus, when overexpansion occurs in the expansion chamber, the lubricating oil can be rapidly injected from the plurality of passages.

  According to the present invention, when an overexpansion phenomenon occurs in the expansion chamber, the overexpansion phenomenon can be suppressed by reducing the volume of the expansion chamber with the injected lubricating oil.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail as examples based on the attached drawings.

  FIG. 1 is a refrigerant circuit including an expander according to the present invention, and FIG. 2 is a cross-sectional view of the first embodiment of the expander. FIG. 3 is a cross-sectional view showing the expansion process of the expansion chamber, and FIG. 4 is a Mollier diagram showing the refrigeration cycle of the expander. FIG. 5 is a sectional view showing an expansion mechanism-integrated compressor in which the compression mechanism and the expansion mechanism are integrated. FIG. 6 is a cross-sectional view showing a second embodiment of the expander, and FIG. 7 is a cross-sectional view showing a third embodiment of the expander. FIG. 8 is a sectional view showing a fourth embodiment.

  The refrigerant circuit 1 including the expander 4 according to the present invention is configured by sequentially connecting a compressor 2, a radiator 3, an expander 4, and a heat absorber 5 as shown in FIG. In the refrigerant circuit 1, for example, a carbon dioxide refrigerant as a natural refrigerant that changes its phase state at a critical pressure or higher circulates. The compressor 2 is composed of a scroll compressor or a rotary compressor, and the radiator 3 and the heat absorber 5 are arranged in parallel with a large number of fins arranged in parallel and the fins. It is composed of a so-called cross fin type fin-and-tube heat exchanger composed of a meandering tube.

  The carbon dioxide refrigerant compressed by the compressor 2 and having a high temperature and high pressure flows into the radiator 3 and releases heat by the radiator 3. The refrigerant that has released the heat flows into the expander 4 and expands in the expander 4 to a low temperature and a low pressure. The low-temperature and low-pressure refrigerant absorbs heat by the heat absorber 5 and then returns to the compressor 2. The refrigerant expanded in the expander 4 is configured to rotate and drive a power recovery shaft 10 (described later) provided in the expander 4 by the expanding energy.

  As shown in FIGS. 2 (A) and 2 (B), the expander 4 in the first embodiment of the present application has a casing 4a formed in a cylindrical shape with the upper and lower surfaces closed, and the inside of the casing 4a. An expansion mechanism portion 6 formed on the upper portion of the upper portion, an oil reservoir chamber 7 formed on the lower side, and a power recovery shaft 10 pivotally supported at the central portion of the casing 4a.

  The expansion mechanism section 6 includes an upper wall 8a, a lower wall 8b, and a side wall 8c, and has a cylinder 8 having a cylindrical inner space, a crankshaft 10b formed on the power recovery shaft 10, and the crankshaft 10b. The ring-shaped eccentric rotor 9 is fitted to the outer peripheral edge of the ring. The eccentric rotor 9 is pivotally supported by the crankshaft 10b eccentrically with respect to the power recovery shaft 10, so that the inner space of the cylinder 8 revolves while sliding one end of the outer peripheral surface against the inner wall surface of the cylinder 8. It is supposed to be.

  The casing 4a has a vane storage portion 12 protruding outward. In the vane storage portion 12, a vane 13 supported so as to be able to advance and retreat in a forward / backward direction in which a front end portion is brought into contact with and slides on the outer peripheral surface of the eccentric rotor 9, a rear portion of the vane 13, and the vane storage portion A spring 14 is provided between the inner wall 12 and the pressing means 14 that presses the vane 13 against the outer peripheral surface of the eccentric rotor 9. An inflow port 16 that includes an on-off valve 16a and introduces a high-pressure refrigerant projects from the casing 4a. A discharge port 17 that communicates with the oil sump chamber 7 is provided on the lower wall 8c of the cylinder 8. The inflow port 16 and the discharge port 17 are disposed so as to face the vane 13.

  An expansion chamber 11 is formed in a space surrounded by one side of the vane 13, the outer peripheral surface of the eccentric rotor 9, and the inner wall surface of the cylinder 8. In addition, the power recovery shaft 10 connected to the eccentric rotor 9 has one end connected to a generator or the like, for example, and the eccentric rotor 9 expands energy of the high-pressure refrigerant flowing into the casing 4a. When the power recovery shaft 10 is rotationally driven by this, the generator connected to the power recovery shaft 10 performs a power generation operation, and thereby, the expansion energy of the refrigerant is wasted. It can be used effectively without any problems.

  Oil 19 is stored in the oil sump chamber 7 formed in the lower portion of the casing 4a, and a low-pressure refrigerant outflow port 18 is formed on the side surface of the oil sump chamber 7. . The high-pressure refrigerant that has flowed from the inflow port 16 expands in the expansion chamber 11 of the expansion portion 6 to become a low-pressure refrigerant, and is discharged from the discharge port 17 to the oil reservoir chamber 7. To the refrigerant circuit.

  The power recovery shaft 10 extends downward so that the lower end of the power recovery shaft 10 is immersed in the oil 19 of the oil reservoir 7, and an oil passage 10 a provided with a check valve 15 is formed in the shaft core. Yes. The crankshaft 10b and the eccentric rotor 9 are provided with oil injection holes 9a that allow the oil passage 10a and the internal space of the cylinder 8 to communicate with each other.

  Next, the operation of the expander 4 will be described. The on-off valve 16a provided in the inflow port 16 opens and closes according to the revolving motion of the eccentric rotor 9. For example, in the vicinity of the power recovery shaft 10, the power recovery shaft 10 An angle sensor (not shown) for detecting the rotation angle is provided, and the opening / closing operation of the on-off valve 16a is performed based on the detected rotation angle. Further, a cam may be attached to the power recovery shaft 10, and the opening / closing operation of the opening / closing valve 16a may be performed in accordance with the rotation operation of the cam.

  The high-pressure refrigerant flowing in from the inflow port 16 revolves the eccentric rotor 9 counterclockwise with the high-pressure, rotates the power recovery shaft 10 connected thereto, and As the volume increases, the volume expands and becomes a low-pressure refrigerant. The refrigerant that has been expanded to a low pressure is discharged from the discharge port 17.

  Next, the expansion process in the expansion chamber 11 will be described with reference to FIG. In the expander 4, during the revolving motion of the eccentric rotor 9, the angular range of the suction process in which high-pressure refrigerant is supplied into the cylinder 8 by the opening / closing operation of the on-off valve 16a, and the expansion process in which the fluid is expanded. The angle range is determined in advance. FIG. 3A shows a process in which the on-off valve 16a is opened and a high-pressure refrigerant flows into the expansion chamber 11, and the eccentric rotor 9 rotates in the direction indicated by the arrow from the state of FIG. Then, the on-off valve 16a is closed, and the supply of the refrigerant to the expansion chamber 11 is stopped.

  FIG. 3B shows a state in which the high-pressure refrigerant that has flowed into the expansion chamber 11 expands and increases the volume of the expansion chamber 11 to rotate the eccentric rotor 9, and the refrigerant expands. As a result, the pressure gradually decreases and the refrigerant moves to a low-pressure refrigerant.

  FIG. 3C shows a state in which the refrigerant expands and the volume of the expansion chamber 11 is maximized. The refrigerant that has dropped to a predetermined pressure due to expansion flows out of the discharge port 17. It has come to go. At this time, the on-off valve 16a is opened, and high-pressure refrigerant is again introduced into the cylinder 8 from the inflow port 16.

  As described above, the expander 4 is designed so that the density ratio between the refrigerant flowing in from the inflow port 16 and the refrigerant flowing out from the discharge port 17, the so-called expansion ratio, is constant. The high-pressure refrigerant is introduced into the cylinder 8 in the angular range of the inflow process, while the refrigerant is expanded at a predetermined expansion ratio in the remaining angular range of the expansion process, and the rotational power is recovered. However, in the vapor compression refrigeration cycle, since the high pressure and low pressure of the refrigeration cycle change due to the temperature change of the object to be cooled and the temperature change of the object to be heated, the pressure ratio also fluctuates and accordingly the inflow of the expander 4 The density of the refrigerant and the outflow refrigerant also varies. In such a case, in the expansion chamber 11, a so-called refrigerant overexpansion phenomenon occurs in which the refrigerant pressure drops to a predetermined value or more, and the power recovery efficiency of the expander 4 is reduced.

  When the refrigerant pressure in the expansion chamber 11 is P1, and the refrigerant pressure in the oil sump chamber 7 is P2, the operation is normally performed in a state of P1> P2. However, when an overexpansion phenomenon occurs in the expansion chamber 11 due to the above-described factors, the refrigerant pressure in the expansion chamber 11 is temporarily lower than the refrigerant pressure in the oil reservoir chamber 7, so-called P1 < The state of P2 occurs. When this state occurs, the pressure of the refrigerant in the oil reservoir 7 is applied to the surface of the stored lubricating oil, and the amount of lubricating oil corresponding to the differential pressure between P1 and P2 is It is sucked into the oil passage 10a and rises.

  The lubricating oil sucked and raised by the oil passage 10a is then injected into the expansion chamber 11 through the oil injection hole 9a. The amount of lubricating oil corresponding to the pressure difference between P1 and P2 is injected into the expansion chamber 11, so that the volume of the expansion chamber 11 decreases according to the amount of injected lubricating oil, and the refrigerant pressure increases again. Thus, the overexpansion phenomenon can be suppressed. Further, the oil passage 10a can be easily provided without the need for a separate member due to the configuration formed in the power recovery shaft 10 and the eccentric rotor 9 in the oil passage 10a.

  The oil 19 that has once risen by the check valve 15 stays in the oil passage 10a and the oil injection hole 9a, and no overexpansion phenomenon occurs in the expansion chamber 11. However, by sealing the injection circuit such as the oil passage 10a and the oil injection hole 9a with an incompressible lubricating oil, the so-called dead volume that does not contribute to the power recovery operation can be reduced as much as possible. It is like that. Furthermore, when gas is used for injection, since the gas is compressible, high-pressure refrigerant from the inflow port 16 may flow into the injection circuit, but the lubricating oil is in a liquid phase only. Since there is almost no change in volume due to a change in pressure, there is no possibility that the refrigerant will flow into the injection circuit. In addition, the installation position of the oil injection hole 9a, the installation position of the check valve 15 and the parts provided in the oil injection hole 9a can be easily selected. With these, an expander capable of efficient operation can be obtained. ing.

  In the expander 4 described above, when the power recovery shaft 10 is rotationally driven, a generator or the like connected to the power recovery shaft 10 performs a power generation operation, and thereby, the expansion energy of the refrigerant is not wasted. Although it can be used effectively, as shown in FIG. 4, the expansion mechanism and the compression mechanism of the compressor can be integrated to effectively use the expansion energy.

  An expander-integrated compressor 100 shown in FIG. 5 houses a compression mechanism section 102, an electric motor section 103, and an expansion mechanism section 104 inside a casing 101. The compression mechanism 102 constitutes a scroll compressor including a fixed scroll 114, a turning scroll 115, and frames 112 and 113, and is provided with a suction port 116 and a discharge port 117. The electric motor unit 103 includes a stator 108, a rotor 109, and a main shaft 105, and the main shaft 105 is connected to the expansion mechanism unit 104.

  The expansion mechanism 104 includes a cylinder 106 and an eccentric rotor 107 that revolves within the cylinder 106, and is provided with an inflow port 11 and an outflow port 110. When the eccentric rotor 107 is rotationally driven by the refrigerant flowing from the inflow port 11, the rotational force of the main shaft 105 connected thereto is urged.

  Thus, the expander-integrated compressor is configured by integrating the compressor and the expander, and the rotational driving force of the expansion mechanism unit 104 drives the compression mechanism unit 102 together with the electric motor unit 103. ing. This can reduce the energy of the motor unit 103 that drives the compression mechanism unit 102 by the amount of power recovered in the process of adiabatic expansion C point → D ′ point shown in the Mollier diagram of FIG. Thus, the energy recovery efficiency can be improved.

  Next, a second embodiment will be described. As shown in FIG. 6, the expander 20 in the second embodiment includes a cylindrical casing 21 whose upper surface and lower surface are closed, and a cylinder formed in the lower part of the casing 21 and having a cylindrical inner space. 22, an eccentric rotor 23 supported in an internal space of the cylinder 22 so as to freely rotate and a power recovery shaft 24 connected to the eccentric rotor 23.

  An outflow port 27 through which the low-pressure refrigerant flows out is provided at the upper side of the casing 21, and an inflow port 29 through which high-pressure refrigerant flows in is provided at the lower side of the casing 21. It communicates with the internal space of the cylinder 22. A suction pipe 28 that communicates with the internal space projects upward from the upper portion of the cylinder 22, and an oil injection hole 30 having a check valve 30 a is formed on the side surface of the cylinder 22. Has been.

  Lubricating oil 25 is stored in the casing 21 so that the cylinder 22 is immersed therein. The high-pressure refrigerant flowing from the inflow port 29 flows into the cylinder 22 as indicated by an arrow, expands in the expansion chamber 26, and becomes low pressure while rotating the eccentric rotor 23 and the power recovery shaft 24. Then, it flows out from the outflow port 27 through the suction pipe 28.

  When an overexpansion phenomenon occurs in the expansion chamber 26 in the cylinder 22, the lubricating oil stored in the casing 21 is injected into the expansion chamber 26 through the oil injection hole 30 to prevent the refrigerant from overexpanding. Be able to. Due to the structure in which the cylinder 22 is immersed in the lubricating oil, the length of the oil injection hole 30 can be shortened as much as possible, the processing is easy, and the lubricating oil can be injected quickly in response to the overexpansion phenomenon. It is like that. Further, the volume of the casing 21 can be minimized as much as possible, and a compact expander 20 can be obtained.

  Next, a third embodiment will be described. As shown in FIG. 7, the expander 31 in the third embodiment is substantially the same as the first embodiment, and the description of the basic configuration is omitted. An arcuate oil passage 36 is formed in the cylinder 32 along the circumferential direction. Further, a plurality of oil injection holes 37 a are formed from the oil passage 36 toward the internal space of the cylinder 32. Has been. A lubricating oil tank 33 is connected to the oil passage 36 by an oil supply passage 34 having a check valve 35.

  A predetermined low pressure P3 is constantly applied to the lubricating oil stored in the lubricating oil tank 33. When an overexpansion phenomenon occurs in the expansion chamber of the expander 31, the lubricating oil stored in the lubricating oil tank 33 is supplied to the oil passage 36 through the oil supply passage 34 by a predetermined low pressure P3. It has become. The lubricating oil supplied to the oil passage 36 is injected into the expansion chamber of the cylinder 32 through a plurality of the oil injection holes 37a, thereby suppressing the refrigerant overexpansion phenomenon. By injecting the lubricating oil from the plurality of oil injection holes 37a, it is possible to respond quickly when overexpansion occurs in the expansion chamber.

  Next, a fourth embodiment will be described. As shown in FIG. 8, the expander 38 in the fourth embodiment is provided with a pressure sensor 42 in an expansion chamber 41 formed by a cylinder 39, an eccentric rotor 40, and a vane. An open / close valve 45 that opens and closes the oil passage 44 of the power recovery shaft 43 based on the detection value of the pressure sensor 42 is provided.

  The high-pressure refrigerant having the pressure P4 flowing in from the inflow port 46 expands in the expansion chamber 41 to become a low-pressure refrigerant, and flows out from the outflow port 46 at the pressure P6. When an overexpansion phenomenon occurs in the expansion chamber 41 and the pressure P5 in the expansion chamber 41 becomes lower than the pressure P6, the pressure sensor 42 detects this and opens the on-off valve 45. It is like that. When the on-off valve 45 is opened, the lubricating oil stored in the oil reservoir chamber is sucked into the oil passage 44 of the power recovery shaft 43 and injected into the expansion chamber 41. As a result, the refrigerant overexpansion phenomenon can be prevented.

It is a refrigerant circuit provided with the expander by this invention. (A) is sectional drawing from the upper direction in 1st Example of the expander by this invention (B) is side sectional drawing in 1st Example of the expander by this invention It is sectional drawing which shows the expansion process of the refrigerant | coolant in an expansion chamber. It is a Mollier diagram which shows the refrigerating cycle in an expander. It is sectional drawing which shows the compression-expansion unit with which the compression mechanism and the expansion mechanism were united. It is a sectional side view in the 2nd Example of the expander by this invention. It is sectional drawing from upper direction in the 3rd Example of the expander by this invention. (A) is sectional drawing from the upper direction in 4th Example of the expander by this invention (B) is side sectional drawing in 4th Example of the expander by this invention It is sectional drawing which shows an example of the conventional expander. (A) And (B) is explanatory drawing which shows the change of the pressure and volume in an expansion chamber.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Refrigerant circuit 2 Compressor 3 Radiator 4 Expander 4a Casing 5 Heat absorber 6 Expansion mechanism part 7 Oil reservoir chamber 8 Cylinder 9 Eccentric rotor 9a Oil injection hole 10 Power recovery shaft 10a Oil passage 10b Crankshaft 11 Expansion chamber 12 Vane storage Part 13 Vane 14 Spring 15 Check valve 16 Inflow port 16a On-off valve 17 Discharge port 18 Outflow port 19 Lubricating oil 20 Expander 21 Casing 22 Cylinder 23 Eccentric rotor 24 Power recovery shaft 25 Lubricating oil 26 Expansion chamber 27 Outflow port 28 Intake pipe 29 Inflow port 30 Oil injection hole 30a Check valve 31 Expander 32 Cylinder 33 Lubricating oil tank 34 Oil supply passage 35 Check valve 36 Oil passage 37a Oil injection hole 38 Expander 39 Cylinder 40 Eccentric rotor 41 Expansion chamber 42 Pressure sensor 43 Power times Shaft 44 oil passage 45 on-off valve 46 inlet port 47 outlet port

Claims (4)

The casing includes an expansion chamber defined by a cylinder, an eccentric rotor, and a vane, and a power recovery shaft that pivotally supports the eccentric rotor, and the working fluid that has flowed into the expansion chamber shifts from a high pressure state to a low pressure state. In the expander that expands while rotating the eccentric rotor and the power recovery shaft connected thereto,
An oil reservoir chamber for storing lubricating oil is provided in the casing, and an oil passage having a backflow preventing means for connecting the oil reservoir chamber and the expansion chamber is provided, and the pressure of the expansion chamber, the oil reservoir An expander characterized by injecting lubricating oil into the expansion chamber from the oil reservoir chamber via the oil passage according to a difference from the pressure in the chamber.   The expander according to claim 1, wherein the oil passage is formed in the power recovery shaft and the eccentric rotor.   The expander according to claim 1, wherein the cylinder and the eccentric rotor are immersed in lubricating oil in the oil reservoir chamber.   2. The oil passage according to claim 1, wherein the oil passage includes an arc-shaped passage formed in a circumferential direction in the cylinder and a plurality of passages connecting the expansion passage to the expansion chamber. Expansion machine.

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