JP2002364562A - Scroll type fluid machine and refrigerating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a scroll type fluid machine to expand a fluid in the supercritical pressure condition into the gas-liquid two phase condition, in which it is possible to secure a recoverable power while large-sized construction is avoided and to reduce the torque variation of the obtained power. SOLUTION: The scroll type fluid machine consists in an expanding mechanism part 60, in which a stationary side lap 63 and a movable side lap 66 are engaged so as to make partitioning into expansion chambers 71 and 72. The thickness of laps 63 and 66 is made smaller in the middle part in the elongating direction of the laps 63 and 66, and the rate of volume change of the expansion chambers 71 and 72 is varied by the rotating angle of the movable scroll 64. In the region where the rate of volume change of the expansion chambers 71 and 72 remain small, the refrigerant expands from the supercritical pressure condition into the saturated liquid condition. In the region where the rate of volume change is large, the refrigerant is turned from the saturated liquid condition into the gas-liquid two phase condition and expansion is continued.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scroll type fluid machine, and more particularly to a scroll type fluid machine which is rotated by expansion of a fluid.

[0002]

2. Description of the Related Art Conventionally, scroll-type fluid machines have been widely known and used as compressors and expanders. For example, a new edition of the Refrigeration and Air Conditioning Handbook
In the fifth edition, Vol. 2, Equipment, pages 37 to 43, a scroll type fluid machine applied to a refrigerant compressor is disclosed. Japanese Patent Application Laid-Open No. 2001-107881 discloses a scroll type fluid machine applied to a refrigerant expander.

As shown in FIG. 12, the scroll type fluid machine has a fixed scroll (a) and a movable scroll (b).
And The fixed scroll (a) and the movable scroll (b) are provided with a spiral wrap (c) that draws an involute curve. The thickness of the wrap (c) is constant over its entire length. In this scroll type fluid machine, the wrap (c) of the fixed scroll (a) and the orbiting scroll (b) are meshed with their phases shifted by 180 °, and a fluid chamber (d) is formed between both wraps (c). You.

In the scroll type fluid machine, the movable scroll (b) revolves around the center of the fixed scroll (a) with a constant turning radius. At that time, the movable scroll (b) revolves without rotating. The volume of the fluid chamber (d) partitioned by the fixed scroll (a) and the movable scroll (b) changes with the revolution of the movable scroll (b). When this scroll-type fluid machine is used as an expander, a high-pressure fluid is introduced from the inlet (e) of the fixed scroll (a) into the fluid chamber (d). Then, the movable scroll (b) is pushed and moved by the fluid in the fluid chamber (d), and the expansion work of the fluid is taken out as rotational power of the movable scroll (b).

[0005]

However, in the case where a conventional scroll-type fluid machine is used as an expander, the following problem arises when a fluid in a supercritical pressure state is expanded to a gas-liquid two-phase state. Had occurred. Here, the problem will be described.

For example, when carbon dioxide (CO ₂ ) is expanded from a supercritical pressure state to a gas-liquid two-phase state, the state of carbon dioxide changes as shown by a solid line in FIG. That is, the carbon dioxide in the state at the point c (supercritical pressure state) expands and the pressure is reduced, and becomes a saturated liquid state at the point d. Thereafter, the carbon dioxide is in a gas-liquid two-phase state, continues to expand, and is in a state of a point e. In this case, during the period from point c to point d, the amount of increase in the specific volume is not so large even if the pressure of carbon dioxide is greatly reduced. On the other hand, during the period from the point d to the point e, the specific volume of the carbon dioxide changes relatively significantly as the pressure of the carbon dioxide changes.

On the other hand, in the conventional scroll type fluid machine, the fluid chamber (d) is moved with the rotation of the movable scroll (b).
Is constantly changing at a constant rate.
Therefore, emphasis is placed on the power recovery from the supercritical pressure state (state at point c) to the saturated liquid state (state at point d).
If the volume change rate of the fluid chamber (d) is set small, the number of turns of the wrap (c) required to obtain a predetermined expansion ratio increases. For this reason, there has been a problem that the fixed scroll (a) and the movable scroll (b) become large, and as a result, the scroll type fluid machine becomes large.

On the contrary, emphasis is placed on power recovery while the fluid expands in a gas-liquid two-phase state (from point d to point e), and the volume change rate of the fluid chamber (d) is reduced. If it is set large, the power recovery from the supercritical pressure state (state at point c) to the saturated liquid state (state at point d) becomes insufficient. Further, as shown in FIG. 13, there is a problem that the characteristic of the fluid changes greatly during the expansion process, so that the torque fluctuation width of the obtained rotational power becomes large.

SUMMARY OF THE INVENTION The present invention has been made in view of the foregoing, and an object of the present invention is to provide a scroll type fluid machine for expanding a fluid in a supercritical pressure state to a gas-liquid two-phase state. While ensuring the recoverable power and reducing the torque fluctuation of the obtained power.

[0010]

According to a first aspect of the present invention, a fixed scroll (61) and a movable scroll (64) each having a spiral wrap (63, 66) are formed.
And fixed scroll (61) and movable scroll (6
This is intended for a scroll type fluid machine in which expansion chambers (71, 72) are formed by engaging the wraps (63, 66) of 4) with each other. Then, the supercritical fluid is supplied to the expansion chamber (7).
1,72), and the fluid expands into a gas-liquid two-phase state and flows out of the expansion chambers (71, 72).
1,72) is a closed space, until the rotation angle of the orbiting scroll (64) reaches a predetermined value.
The volume of 2) increases at the first rate of change, and the movable scroll (6
When the rotation angle of 4) exceeds the predetermined value, the volume of the expansion chamber (71, 72) increases at the second rate of change, and the first rate of change becomes smaller than the second rate of change. It is configured in.

According to a second aspect of the present invention, in the first aspect, the volume change rate of the expansion chamber (71, 72) is changed to the first change rate with the rotation of the movable scroll (64). Laps (63,66) to change from to the second rate of change
Is to change the wall thickness.

According to a third aspect of the present invention, in the above-mentioned second aspect, the wrap (63, 66) is provided from the center end of the wrap (63, 66) to the outer end. The thickness of the wrap (63, 66) gradually decreases as the wrap (63, 66) progresses in the direction of extension, and the thickness of the wrap (63, 66) continues to the end of the thickness decrease and progresses in the extension direction. A thickness increasing portion having a gradually increasing thickness is formed.

According to a fourth aspect of the present invention, in the above-mentioned second aspect, the wrap (63, 66) is provided from the center end to the outer end of the wrap (63, 66). A thickness reduction portion (81) in which the thickness of the wrap (63, 66) gradually decreases as the wrap (63, 66) progresses in the extending direction, and a thickness of the wrap (63, 66) which is continuous with the end of the thickness reduction portion (81). A thin portion (82) whose thickness is kept constant, and a thick portion (continuous to the terminal end of the thin portion (82) and in which the thickness of the wrap (63, 66) increases gradually in the extension direction. 83) is formed.

According to a fifth aspect of the present invention, in the second or the third aspect, the wrap (63, 66) is
The base circle radius of the involute curve which is formed in an involute curve over the entire length of the wrap (63, 66) and represents the shape of the wrap (63, 66) is increased or decreased according to the angle of expansion of the involute curve. The above wrap (63,6
It changes the thickness of 6).

According to a sixth aspect of the present invention, in the above-mentioned second or fourth aspect, the inner and outer surfaces of the wrap (63, 66) include an involute curved portion and an arc-shaped portion. The wrap (63,6
It changes the thickness of 6).

According to a seventh aspect of the present invention, in the first or second aspect, the expansion chambers (71, 72) are
The first expansion chamber (71) and the second expansion chamber (72) are formed as a pair, and the closing completion time of the first expansion chamber (71) is determined by the second expansion chamber (71). 72), and the start time of fluid outflow from the first expansion chamber (71) is later than the start time of fluid outflow from the second expansion chamber (72). It is something that is exposed.

According to an eighth aspect of the present invention, in the seventh aspect, the expansion ratio in the first expansion chamber (71) is equal to the expansion ratio in the second expansion chamber (72). It is configured as follows.

According to a ninth solution of the present invention, the fixed scroll (61) according to the seventh or the eighth solution is used.
Wrap (6)
3) is extended to the vicinity of the outer peripheral end of the other wrap (66).

According to a tenth aspect of the present invention, there is provided a refrigeration apparatus, comprising: a scroll type fluid machine (60) and a refrigerant compressor (50) according to any one of claims 1 to 9; Is connected, and a refrigerant circuit (20) filled with carbon dioxide as a refrigerant is provided. When the refrigerant circuit (20) circulates the refrigerant to perform a refrigeration cycle, the compressor (50) The compressor is compressed to a pressure not lower than the critical pressure of the refrigerant, and the compressed refrigerant is expanded by the scroll fluid machine (60) and recovered power is used for driving the compressor (50).

In the first solution, the expansion chamber (71, 72) is closed while the expansion chamber (71, 72) is closed.
In the period from the time when the closing in (1, 72) is completed to the time when the fluid starts to flow out, the volume change rate of the expansion chambers (71, 72) accompanying the rotation of the orbiting scroll (64) varies. Specifically, after the closing of the expansion chambers (71, 72) is completed, the orbiting scroll (64) revolves by a predetermined angle until the expansion chambers (71, 7) revolve.
The volume change rate in 2) is the first change rate. On the other hand, when the orbiting scroll (64) has moved by a predetermined angle or more, the volume change rate of the expansion chambers (71, 72) becomes the second change rate. Then, in this solution, the first rate of change is smaller than the second rate of change. In other words, movable scroll (64)
Until the rotation angle of the expansion chamber reaches the predetermined value, the volume of the expansion chamber (71, 72) gradually increases as compared to after the rotation angle exceeds the predetermined value.

In the second solution, the wrap (6) formed on the fixed scroll (61) or the movable scroll (64) is used.
3,66), the thickness of which varies from place to place. Then, by increasing or decreasing the thickness of the wrap (63, 66), the volume change rate of the expansion chamber (71, 72) is changed from the first change rate to the second change rate.

In the third solution, the wrap (63, 6
In the elongation direction of 6), the reduced thickness portion and the increased thickness portion are successively formed in order. In the reduced thickness area, wrap (6
The wall thickness of the wrap (63, 66) gradually decreases as the wrap (63, 66) advances in the extension direction of (3, 66). In the thickened portion, as the wrap (63, 66) advances in the extension direction, the wrap (63, 66)
Gradually becomes thicker.

In the fourth solution, the wrap (63, 6
In the extension direction of 6), the reduced thickness portion, the thinned portion (82), and the increased thickness portion (83) are sequentially formed in order. In the reduced thickness portion (81), the thickness of the wrap (63, 66) gradually decreases as the wrap (63, 66) advances in the extension direction. In the thin portion (82), the thickness of the wrap (63, 66) is kept constant at the thickness at the end of the reduced thickness portion (81). In the thickened portion (83), the thickness of the wrap (63, 66) gradually increases as the wrap (63, 66) advances in the extension direction.

In the fifth solution, the thickness of the involute curved wrap (63, 66) is changed by increasing or decreasing the base circle radius of the involute curve. Specifically, as the base circle radius of the involute curve decreases, the thickness of the wrap (63, 66) gradually decreases, and as the base circle radius of the involute curve increases, the wrap (63, 66) decreases. ) Gradually increases in thickness.

In the sixth solution, the wrap (63, 6
The part curved in an involute curve and the part curved in an arc are alternately formed inside and outside of 6). By forming such two portions alternately, the thickness of the wrap (63, 66) is changed depending on the location.

In the seventh solution, the first expansion chamber (71) is rotated while the orbiting scroll (64) rotates.
Is different from a period in which the second expansion chamber (72) is a closed space. This will be described.

First, in the present solution, the first expansion chamber (71) and the second expansion chamber (72) have different timings for completing the closing. That is, even after the inflow of the fluid into the second expansion chamber (72) is completed, the fluid continues to flow into the first expansion chamber (71). Then, after the movable scroll (64) has revolved by a predetermined angle from the time when the closing of the second expansion chamber (72) is completed, the closing of the first expansion chamber (71) is completed. Thereafter, the fluid expands in each of the expansion chambers (71, 72), and the expansion work of the fluid is performed by the movable scroll (64).
It is taken out as the rotational power of. At that time, each expansion chamber (7
1, 72), the internal pressures of the respective expansion chambers (71, 72) at a certain moment are different from each other.

Further, according to the present invention, in the first expansion chamber (71) and the second expansion chamber (72), fluid is supplied to the expansion chamber (7).
1,72) are different from each other. That is, even after the fluid starts flowing out of the second expansion chamber (72), the fluid continues to expand in the first expansion chamber (71). Then, after the movable scroll (64) has revolved by a predetermined angle from the time when the fluid starts flowing out of the second expansion chamber (72), the fluid starts flowing out of the first expansion chamber (71).

In the eighth solution, the expansion ratios of the pair of expansion chambers (71, 72) are equal to each other. That is, the pressure of the fluid flowing out of the expansion chambers (71, 72) is the same for each of the paired expansion chambers (71, 72). Here, the expansion ratio is the ratio of the volume of the expansion chamber (71, 72) immediately after the closing is completed to the volume of the expansion chamber (71, 72) immediately before the start of fluid outflow.

According to the ninth solution, the wrap (63) of the fixed scroll (61) and the wrap (66) of the movable scroll (64) are engaged with each other, and one of the outer peripheral ends is engaged. It is formed in a predetermined shape so as to be located near the other outer end. The first or second expansion chamber (71, 7
The fluid flowing out from 2) is sent out of the expansion chambers (71, 72) from near the outer peripheral end of each wrap (63, 66). That is, the fluid in both expansion chambers (71, 72) is wrapped (63, 66)
Flows out of the expansion chambers (71, 72) at substantially the same position in the circumferential direction of the airbag.

In the tenth solution means, a refrigeration system (10) using the scroll type fluid machine (60) according to the present invention is constituted. In the refrigeration system (10), the scroll fluid machine (60) is connected to the refrigerant circuit (20) together with the refrigerant compressor (50). The refrigerant circuit (20) is filled with carbon dioxide (CO ₂ ) as a refrigerant.

In the refrigerant circuit (20), carbon dioxide as a refrigerant circulates, and a refrigeration cycle is performed. Specifically, the refrigerant is compressed in the compressor (50), and the pressure is raised to a value higher than the critical pressure of the refrigerant (CO ₂ ). The refrigerant discharged from the compressor (50) radiates heat to, for example, air. The refrigerant after heat release is
The fluid flows into the scroll fluid machine (60) as an expander. In the scroll type fluid machine (60), the expansion work of the refrigerant is taken out as rotational power. The rotational power taken out by the scroll fluid machine (60) is used as power for driving the compressor (50) to compress the refrigerant. The expanded refrigerant that has flowed out of the scroll fluid machine (60) absorbs heat from, for example, air or the like, is then sucked into the compressor (50), and is compressed again.

[0033]

According to the present invention, in the scroll type fluid machine, the volume change rate of the expansion chambers (71, 72) is reduced for a while after the expansion of the fluid in the expansion chambers (71, 72) starts. Can be. Therefore, the volume change rate of the expansion chamber (71, 72) is reduced in the process where the fluid in the supercritical pressure state becomes a saturated liquid, and the expansion chamber (71, 72) in the process where the fluid expands in the gas-liquid two-phase state. ) Can be increased.

Therefore, according to the present invention, the wrap (63, 6
6) The volume change rate of the expansion chambers (71, 72) can be made suitable for the process in which the fluid in the supercritical pressure state becomes a saturated liquid without increasing the number of turns in 6), and the scroll fluid machine becomes larger. Can be avoided. Further, according to the present invention, the expansion chamber (71, 7
Compared with the conventional scroll fluid machine in which the volume change rate is constant in 2), sufficient power recovery is possible even in the process where the fluid in the supercritical pressure state becomes a saturated liquid. Further, according to the present invention, the expansion chamber (71, 7
2) Since the volume change rate can be changed, the torque fluctuation width of the rotational power obtained by the expansion of the fluid can be reduced.

Particularly, in the seventh solution, the first expansion chamber (71) and the second expansion chamber (72) formed as a pair.
With respect to (1) and (2), the respective closing completion times and the outflow start times of the fluid are different. For this reason, according to the present solution, the fluctuation range of the rotational force applied to the orbiting scroll (64) due to the expansion of the fluid in the expansion chambers (71, 72) can be reduced, and can be obtained by the scroll fluid machine (60) The torque fluctuation width of the rotating power can be further reduced.

Further, in the above-mentioned seventh solution, the closing completion timing of the first expansion chamber (71) and the second expansion chamber (72) are shifted from each other. , 72) completes the confinement at the same time, compared to the one that completes the confinement, the fluid inlet (69)
The flow velocity of the fluid through is reduced. Therefore, the inlet (69)
Pressure loss of the fluid when passing through,
The pressure of the fluid flowing into the expansion chambers (71, 72) can be kept high. Therefore, according to the present solution, the fluid flowing into the scroll type fluid machine (60) as the expander includes:
A sufficient pressure difference with the fluid flowing out therefrom can be secured, and the rotational power that can be taken out by the scroll type fluid machine (60) can be improved.

According to the ninth solution, the wrap (63, 66) of the fixed scroll (61) or the movable scroll (64) is formed in a predetermined shape. For this reason, the expansion chambers (71, 72) start from the substantially same position in the circumferential direction of the wrap (63, 66).
The fluid inside can be discharged.

Here, when the conventional scroll type fluid machine shown in FIG. 12 is used as an expander, the fluid in the expansion chamber (d) flows out from a position 180 ° apart in the circumferential direction of the wrap (c). . Therefore, if the port of the fluid from the scroll type fluid machine is to be provided only at one location, the fluid flowing out of one of the expansion chambers (d) flows around the outside of the wrap (c) and flows out. It will be led to the port.
Then, while bypassing the outside of the wrap (c), the fluid flowing out of the expansion chamber (d) absorbs heat, and the enthalpy of the fluid sent out from the scroll type fluid machine increases.

On the other hand, according to the present solution, the expansion chambers (71, 72) start from substantially the same position in the circumferential direction of the wrap (63, 66).
It is possible to drain the fluid inside. Therefore, the fluid flowing out of the expansion chambers (71, 72) can be immediately guided to one outflow port (37), and the enthalpy of the fluid sent out from the scroll type fluid machine (60) can be prevented from increasing.

In the tenth solution, the scroll type fluid machine (60) according to the present invention is provided in the refrigeration system (10) as an expander, and the expansion work of the refrigerant is recovered as rotational power, and further recovered. The rotating power is used to drive the compressor (50). Therefore, according to the present solution, energy such as electric power supplied from the outside to compress the refrigerant in the compressor (50) can be reduced, and the COP (coefficient of performance) of the refrigeration system (10) can be improved. it can.

[0041]

Embodiment 1 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Embodiment 1 is an air conditioner (10) configured by the refrigeration apparatus according to the present invention.

<< Overall Configuration of Air Conditioner >> As shown in FIG.
The air conditioner (10) is a so-called separate type, and includes an outdoor unit (11) and an indoor unit (13). The outdoor unit (11) includes an outdoor fan (12) and an outdoor heat exchanger (2
3), the first four-way switching valve (21), the second four-way switching valve (22),
And a compression / expansion unit (30). The indoor unit (13) includes an indoor fan (14) and an indoor heat exchanger (2
4) is stored. The outdoor unit (11) is installed outdoors, and the indoor unit (13) is installed indoors. The outdoor unit (11) and the indoor unit (13) are connected by a pair of communication pipes (15, 16). The details of the compression / expansion unit (30) will be described later.

The air conditioner (10) is provided with a refrigerant circuit (20). The refrigerant circuit (20) is a closed circuit to which the compression / expansion unit (30), the indoor heat exchanger (24), and the like are connected. The refrigerant circuit (20) is filled with carbon dioxide (CO ₂ ) as a refrigerant.

Each of the outdoor heat exchanger (23) and the indoor heat exchanger (24) is a cross-fin type fin and
It consists of a tube heat exchanger. Outdoor heat exchanger (2
In 3), the refrigerant circulating in the refrigerant circuit (20) exchanges heat with outdoor air. In the indoor heat exchanger (24), the refrigerant circuit (20)
The refrigerant circulating through the heat exchanger exchanges heat with room air.

The first four-way switching valve (21) has four ports. The first four-way switching valve (21) has a first port connected to the discharge port (3) of the compression / expansion unit (30).
5), and the second port is connected to one end of the indoor heat exchanger (24) via the connecting pipe (15), and the third port is connected to the third port.
Port is connected to one end of the outdoor heat exchanger (23) by piping.
The fourth port is connected to the suction port (34) of the compression / expansion unit (30) by piping. The first four-way switching valve (21) is in a state where the first port and the second port are in communication and the third port and the fourth port are in communication (a state indicated by a solid line in FIG. 1). And a state where the first port and the third port communicate with each other and the second port and the fourth port communicate with each other (a state shown by a broken line in FIG. 1).

The second four-way switching valve (22) has four ports. The second four-way switching valve (22) has a first port connected to the outflow port (3) of the compression / expansion unit (30).
7) and the second port is connected to the outdoor heat exchanger (2
3) is connected to the other end of the pipe, and the third port is connected to the connecting pipe (1
The second port is connected to the other end of the indoor heat exchanger (24) via 6), and the fourth port is connected to the outflow port (37) of the compression / expansion unit (30). The first four-way switching valve (21) is in a state where the first port and the second port are in communication and the third port and the fourth port are in communication (a state indicated by a solid line in FIG. 1). And a state where the first port and the third port communicate with each other and the second port and the fourth port communicate with each other (a state shown by a broken line in FIG. 1).

<< Structure of Compression / Expansion Unit >> As shown in FIG. 2, the compression / expansion unit (30) includes a compression mechanism (50) inside a casing (31), which is a vertically long cylindrical hermetic container. And an expansion mechanism (60) and a motor (40). The casing (31) of the compression / expansion unit (30) is provided with a suction port (34), a discharge port (35), an inflow port (36), and an outflow port (37).

Inside the casing (31), a frame (67) is provided slightly above the center in the height direction. The frame (67) divides the internal space of the casing (31) into an upper space (32) above the frame (67) and a lower space (33) below the frame (67). The expansion mechanism (60) is installed in the upper space (32) in the casing (31), and the compression mechanism (50) and the motor (40) are installed in the lower space (33). In the lower space (33), the motor (40)
Is disposed above the compression mechanism (50).

The motor (40) includes a stator (41) and a rotor (42). The stator (41) is fixed to the casing (31). The rotor (42) is arranged inside the stator (41). A drive shaft (45) penetrates through the rotor (42) coaxially with the rotor (42). The lower end of the drive shaft (45) is connected to the compression mechanism (50), and the upper end of the drive shaft (45) is the expansion mechanism (60).
It is connected to.

The compression mechanism (50) is configured as a so-called swing type rotary compressor. The compression mechanism (50) includes a cylinder (51), a piston (53) housed in a cylinder chamber (52) of the cylinder (51), and a front head ( 54)
And a rear head (55) for closing the lower surface of the cylinder chamber (52). The lower end of the drive shaft (45) penetrates from the front head (54) to the rear head (55) via the cylinder (51).

The piston (53) is formed in an annular shape, and is rotatably fitted to the lower end of the drive shaft (45). The lower end of the drive shaft (45) into which the piston (53) is fitted constitutes a lower eccentric shaft (46). The lower eccentric shaft (46) is formed eccentrically from the axis of the drive shaft (45).

Although not shown, the piston (53)
The blade is integrally formed. The blade is inserted into the cylinder (51) via a bush. Then, the piston (53) swings around the bush, thereby reducing the volume in the cylinder chamber (52) and compressing the refrigerant.

The cylinder (51) is provided with a refrigerant suction port (57). The suction port (34) is connected to the suction port (57). The front head (54) has a refrigerant discharge port (58). The front head (54) is provided with a discharge valve (56) for opening and closing the discharge port (58). This outlet (58)
Opens into the lower space (33) in the casing (31). One end of the discharge port (35) is open near the upper end of the lower space (33).

The expansion mechanism (60) constitutes a scroll type fluid machine. The expansion mechanism (60) includes a fixed scroll (61) and a movable scroll (64). The frame (67) not only partitions the inside of the casing (31) up and down, but also constitutes the expansion mechanism (60).

The fixed scroll (61) includes a head plate (62)
And a spiral fixed wrap (63) projecting to the lower surface side of the end plate (62). The end plate (62) of the fixed scroll (61) is fixed to the casing (31). On the other hand, the movable scroll (64) is a plate-like end plate (65).
And a spiral fixed side wrap (63) protruding toward the upper surface of the end plate (62). The fixed scroll (61) and the orbiting scroll (64) are arranged so as to face each other, and the fixed-side wrap (63) and the movable-side wrap (66)
The expansion chambers (71, 72) are defined by meshing with each other.

A coolant inlet (69) is formed at the center of the end plate (62) of the fixed scroll (61). The inflow port (69) is connected to the expansion chamber (71, 72) and the upper space (32).
In order to communicate with the fixed scroll (61), it is formed through the end plate (62) of the fixed scroll (61). At the top of the casing (31), an inflow port (36) for introducing a refrigerant into the upper space (32) is provided. At the outer peripheral side of the fixed wrap (63) and the movable wrap (66), the refrigerant outlet (7
0) is formed. The outflow port (37) is connected to the outflow port (70).

The end plate (65) of the movable scroll (64)
Has a shape in which a central portion on the lower surface side protrudes downward, and this protruding portion is rotatably fitted to an upper end portion of the drive shaft (45). The upper end of the drive shaft (45) into which the end plate (65) is fitted constitutes an upper eccentric shaft (47). The upper eccentric shaft (47) is formed eccentrically from the axis of the drive shaft (45). Also drive shaft (45)
A flange-shaped flange (48) is formed directly below the upper eccentric shaft (47). The thrust load acting on the orbiting scroll (64) is adjusted by the flange (48) of the drive shaft (45) and the frame (6).
7) and received by.

The movable scroll (64) is supported by a frame (67) via an Oldham ring (68). The Oldham ring (68) is for restricting rotation of the movable scroll (64). Then, the orbiting scroll (64) revolves at a predetermined turning radius without rotating. The turning radius of the orbiting scroll (64) is the same as the amount of eccentricity of the upper eccentric shaft (47).

As shown in FIG. 3, the fixed side wrap (63) and the movable side wrap (66) are formed in the same spiral shape. In other words, the number of turns of the fixed side wrap (63) and the number of turns of the movable side wrap (66) are equal, and the thicknesses of both are similarly increased or decreased. The shapes of the fixed wrap (63) and the movable wrap (66) will be described later. And
The movable-side wrap (66) and the fixed-side wrap (63) formed in this way are engaged with each other in a state where their phases are shifted from each other by 180 °. In FIG. 3, the fixed scroll (6
The outline of the end plate (62) of 1) is omitted.

By engaging the movable wrap (66) and the fixed wrap (63) as described above, the first chamber (71) as the first expansion chamber and the second chamber as the second expansion chamber are engaged. (72)
Are formed as a pair. That is, the first chamber (71) is formed between the outer surface of the movable wrap (66) and the inner surface of the fixed wrap (63), and the outer surface of the fixed wrap (63) and the movable wrap (63) are formed. A second chamber (72) is formed sandwiched between the inner surface of (66). In addition, in the end plate (62) of the movable wrap (66), a refrigerant inlet (69) is circularly opened near the center side end of the movable wrap (66).

The shapes of the fixed wrap (63) and the movable wrap (66) will be described with reference to FIG.
Since the fixed side wrap (63) and the movable side wrap (66) have the same shape as described above, only the shape of the fixed side wrap (63) will be described here.

The fixed side wrap (63) is shaped such that its thickness increases and decreases as it extends in the extending direction from the center end to the outer end. In order to change the wall thickness in this manner, the outer side surface and the inner side surface of the fixed side wrap (63) are formed by combining an arc and an involute curve. The fixed side wrap (63) is formed such that the thickness at the center end and the thickness at the outer end are the same. Further, in FIG. 4, the shape of the fixed side wrap (63) assuming that the thickness of the fixed side wrap (63) is kept constant over the entire circumference is indicated by a two-dot chain line.

The outer side surface of the fixed side wrap (63) is formed such that the curve drawn by the lower end side, that is, the outer peripheral line has the following shape. At the center end of the fixed side wrap (63), that is, at the portion from the start of winding of the outer peripheral line until the winding angle becomes about 90 °, the outer peripheral line draws a first arc. In the portion from the end of the first arc to the winding angle of the outer peripheral line of about 360 °, the outer peripheral line describes a first involute curve. In the portion from the end of the first involute curve to the winding angle of the outer peripheral line of about 450 °, the outer peripheral line describes a second arc. From the end of the second arc to the end of the winding of the outer peripheral line, the outer peripheral line describes a second involute curve.

On the other hand, the inner side surface of the fixed side wrap (63) is formed such that the curve drawn by the lower side, that is, the inner peripheral line has the following shape. At the center end of the fixed side wrap (63), that is, at the portion from the start of winding of the inner peripheral line until the winding angle becomes about 180 °, the inner peripheral line describes a third involute curve. In a portion from the end of the third involute curve to a point where the winding angle of the inner circumference becomes approximately 270 °, the inner circumference draws a third arc. In the portion from the end of the third circular arc to the point where the winding angle of the inner circumference becomes approximately 540 °, the inner circumference draws a fourth involute curve. In the portion from the end of the fourth involute curve to the winding angle of the inner peripheral line being about 630 °, the inner peripheral line is the fourth involute curve.
Draws an arc. Then, from the end of the fourth arc to the end of winding of the inner peripheral line, the inner peripheral line describes a fifth involute curve.

The thickness of the fixed side wrap (63) formed in this manner increases or decreases as follows. In a portion where the outer peripheral line is the first arc and the inner peripheral line is the third involute curve, the thickness of the fixed wrap (63) gradually increases. In the portion where the outer peripheral line is the first involute curve and the inner peripheral line is the third involute curve, the thickness of the fixed side wrap (63) is kept constant. The thickness of the fixed side wrap (63) in this portion is larger than the thickness of the center side end portion or the outer peripheral side end portion. In a portion where the outer peripheral line is the first involute curve and the inner peripheral line is the third arc, the thickness of the fixed side wrap (63) is gradually reduced. In the portion where the outer peripheral line is the first involute curve and the inner peripheral line is the fourth involute curve, the thickness of the fixed side wrap (63) is kept constant. The thickness of the fixed side wrap (63) in this portion is equal to the thickness of the center side end portion and the outer peripheral side end portion.

Subsequently, in a portion where the outer peripheral line is the second arc and the inner peripheral line is the fourth involute curve, the thickness of the fixed side wrap (63) is gradually reduced. This part
It constitutes a reduced thickness portion (81). In a portion where the outer peripheral line is the second involute curve and the inner peripheral line is the fourth involute curve, the thickness of the fixed side wrap (63) is kept constant. In this portion, the thickness of the fixed-side wrap (63) is smaller than the thickness of the center-side end and the outer-peripheral-side end, and forms a thin-walled portion (82). In a portion where the outer peripheral line is the second involute curve and the inner peripheral line is the fourth arc, the thickness of the fixed side wrap (63) gradually increases. This portion constitutes a thickened portion (83). In the portion where the outer line is the second involute curve and the inner line is the fifth involute curve, the fixed side wrap (6
3) The thickness is kept constant. The thickness of the fixed side wrap (63) in this portion is equal to the thickness of the center side end portion and the outer peripheral side end portion.

As described above, the expansion chambers (71, 72) are formed by engaging the movable wrap (66) with the fixed wrap (63). Further, by increasing or decreasing the thickness of the movable wrap (66) and the fixed wrap (63) as described above, the volume change rate of the expansion chamber (71, 72) can be reduced.
It is configured to change according to the value of the rotation angle of 6).

-Operation- The operation of the air conditioner (10) will be described. here,
The operation of the air conditioner (10) during the cooling operation and the heating operation will be described, and then the operation of the expansion mechanism (60) will be described.

<< Cooling Operation >> During the cooling operation, the first four-way switching valve (21) and the second four-way switching valve (22) are switched to the state shown by the broken line in FIG. When the motor (40) of the compression / expansion unit (30) is energized in this state, the refrigerant circuit (20)
Then, the refrigerant circulates, and a refrigeration cycle as shown in a Mollier diagram (pressure-enthalpy diagram) in FIG. 5 is performed.

The point a in FIG. 5 is applied to the compression mechanism (50).
Is sucked. In the compression mechanism (50), the refrigerant is compressed from the state at point a to the state at point b. still,
The pressure in the state at the point b is the carbon dioxide (C
O ₂ ) is higher than the critical pressure. The refrigerant in the state at the point b is discharged into the lower space (33) in the casing (31), passes through the discharge port (35), and then flows into the casing (31).
Out of Thereafter, the refrigerant in the state of the point b is
It is sent to the outdoor heat exchanger (23) through the first four-way switching valve (21).

In the outdoor heat exchanger (23), the inflow refrigerant exchanges heat with outdoor air sent by the outdoor fan (12). Due to this heat exchange, the refrigerant in the state of the point b is radiated to the outdoor air to be in the state of the point c. The refrigerant in the state at the point c passes through the second four-way switching valve (22), flows into the upper space (32) of the compression / expansion unit (30) through the inflow port (36), and further expands. Flow into section (60).

In the expansion mechanism (60), the inflowing refrigerant expands in the isentropic process, and the state at the point c (supercritical pressure state)
Changes from the state at point d (saturated liquid state) to the state at point e (gas-liquid two-phase state). In FIG. 5, points c, d,
Point e corresponds to points c, d, and e in FIG.

Here, when the refrigerant is expanded by the expansion valve, the refrigerant expands in an adiabatic expansion process (isenthalpy process) as shown by a broken line in FIG. On the other hand, in the expansion mechanism (60), the refrigerant expands in the isentropic process, and both the pressure and the enthalpy of the refrigerant decrease. The refrigerant in the state at the point e flowing out of the expansion mechanism (60) flows out of the compression / expansion unit (30) through the outflow port (37),
After passing through the second four-way switching valve (22), it is sent to the indoor heat exchanger (24).

In the indoor heat exchanger (24), the inflowing refrigerant exchanges heat with the indoor air sent by the indoor fan (14). Due to this heat exchange, the refrigerant in the state at the point e absorbs heat from the room air to become the state at the point a, and the room air is cooled.
The refrigerant in the state of the point a passes through the first four-way switching valve (21),
It is sucked into the compression mechanism (50) of the compression / expansion unit (30) through the suction port (34). Then, the compression mechanism (50) compresses the drawn refrigerant again and discharges it, and this circulation is repeated.

[0075] Here, in the expansion mechanism (60), the inflow refrigerant is inflated from the state of point c until the state of point e, rotational power corresponding to the enthalpy decrease amount W _E of the refrigerant is recovered (See FIG. 5). This recovered rotational power is
It is transmitted to the compression mechanism (50) by the drive shaft (45) and is used to rotate the piston (53) of the compression mechanism (50). The motor (40) is connected to the compression mechanism (50).
Rotational power W _C is transmitted, is used for the piston (53) is driven to rotate together with the rotational force W _E transmitted from the expansion mechanism (60) by.

<< Heating Operation >> During the heating operation, the first four-way switching valve (21) and the second four-way switching valve (22) are switched to the state shown by the solid line in FIG. When the motor (40) of the compression / expansion unit (30) is energized in this state, the refrigerant circuit (20)
Circulates the refrigerant to perform a refrigeration cycle.

Specifically, the refrigerant compressed by the compression mechanism (50) flows out of the compression / expansion unit (30) through the discharge port (35) and passes through the first four-way switching valve (21). Then, it is sent to the indoor heat exchanger (24). In the indoor heat exchanger (24), the inflowing refrigerant exchanges heat with indoor air. By this heat exchange, the refrigerant radiates heat to the room air, and the room air is heated. The refrigerant radiated by the indoor heat exchanger (24) passes through the second four-way switching valve (22), flows into the expansion mechanism (60) through the inflow port (36).

In the expansion mechanism (60), the inflowing refrigerant expands in an isentropic process. The expanded refrigerant flows out of the compression / expansion unit (30) through the outflow port (37), passes through the second four-way switching valve (22), and passes through the outdoor heat exchanger (2).
3). In the outdoor heat exchanger (23), the inflowing refrigerant exchanges heat with the outdoor air, and the refrigerant absorbs heat from the outdoor air. The refrigerant having absorbed the heat passes through the first four-way switching valve (21), passes through the suction port (34), and then enters the compression / expansion unit (3).
It is sucked into the compression mechanism (50) of (0). Compression mechanism (5
0) compresses and discharges the sucked refrigerant again, and this circulation is repeated.

<Operation of Expansion Mechanism> The operation of the expansion mechanism (60) will be described. Supercritical pressure refrigerant flows into the expansion chambers (71, 72) defined by the fixed wrap (63) and the movable wrap (66) through the inflow port (69) (see FIG. 3). When the movable scroll (64) revolves counterclockwise in FIG. 3, the closing of the expansion chambers (71, 72) is completed.

Thereafter, the movable scroll (64) is pushed and moved by the refrigerant in the expansion chambers (71, 72), and rotational power is applied to the movable scroll (64). Movable scroll (6
As 4) rotates, the expansion chambers (71, 72) increase in volume while being kept in a sealed state. As the orbiting scroll (64) further rotates, the refrigerant in the expansion chambers (71, 72) flows into the expansion chamber (71) near the outer peripheral end of the fixed wrap (63) and the movable wrap (66). , 72).

As described above, the volume of the expansion chamber (71, 72) increases as the orbiting scroll (64) rotates. Here, the volume change rate of the expansion chambers (71, 72) will be described with reference to FIG.

In FIG. 6, the horizontal axis is the movable scroll (64).
And the vertical axis is the projected area of the expansion chamber (71, 72), and the change in the projected area is shown. The projection area of the expansion chamber (71, 72) here refers to the cross-sectional area of the expansion chamber (71, 72) shown in FIG. The volume of the expansion chambers (71, 72) is a value obtained by multiplying the projection area by the height h of the fixed-side wrap (63) and the movable-side wrap (66). Further, the expansion chamber when the rotation angle of the movable scroll (64) becomes theta ₁ (71 and 72)
Was included closing is complete, then the expansion chamber to the rotation angle of the movable scroll (64) becomes the theta ₃ (71 and 72) is maintained in a closed state.

While the rotation angle of the movable scroll (64) is between θ ₁ and θ ₂ , the volume of the expansion chamber (71, 72) increases at the first rate of change. The rotation angle of the movable scroll (64) is θ ₁
Let S _{1 be} the projected area of the expansion chamber (71, 72) at the time
When the projected area of the expansion chamber (71, 72) in the point of time when the rotation angle of theta ₂ of the movable scroll (64) and S _2, the first rate of _{change, (S 2 -S 1) ·} h / (θ 2 −θ ₁ ). On the other hand, during the rotation angle of the movable scroll (64) from theta ₂ to theta ₃ is the volume of the expansion chamber (71, 72) are slide into increased at a second rate of change. When the rotation angle of the movable scroll (64) is a projection area of the expansion chamber (71, 72) at the time of the theta ₃ and S _3, the second rate of _{change, (S 3 -S 2) ·} h / (θ 3 −θ ₂ ).

In the expansion mechanism (60), the first change rate is smaller than the second change rate by increasing or decreasing the thickness of the fixed wrap (63) or the movable wrap (66). Have been. This corresponds to expanding the refrigerant in the supercritical pressure state to the gas-liquid two-phase state in the expansion mechanism (60).

Specifically, the refrigerant that has flowed into the expansion chambers (71, 72) in the supercritical pressure state (the state at the point c in FIGS. 5 and 13) expands, the pressure gradually decreases, and the movable scroll ( When the rotation angle of (64) becomes θ ₂ , a saturated liquid state (state at point d in FIGS. 5 and 13) is established. In other words, during the period from _one rotation angle of the movable scroll (64) is theta to theta _2, in response to variation of the specific volume due to the pressure drop of the refrigerant is small, the volume change rate of the expansion chamber (71, 72) Is set small.

On the other hand, the refrigerant in the saturated liquid state (the state at the point d in FIGS. 5 and 13) in the expansion chambers (71, 72) is:
A gas-liquid two-phase state immediately after the rotation angle of the movable scroll (64) exceeds theta _2. The refrigerant is subsequently expanded to gradually decrease the pressure, Figure 5 when the rotation angle of the movable scroll (64) becomes theta _3, the state of point e in FIG. 13. That is, when the rotation angle of the movable scroll (64) is between θ ₂ and θ ₃ , the volume change rate of the expansion chambers (71, 72) corresponds to the large change in the specific volume due to the pressure drop of the refrigerant. Is set large.

-Effects of First Embodiment- In the first embodiment, the volume change rate of the expansion chambers (71, 72) is changed according to the rotation angle of the orbiting scroll (64).
For this reason, the volume change rate of the expansion chamber (71, 72) is reduced in the process where the fluid in the supercritical pressure state becomes a saturated liquid, and the expansion chamber (71, 72) is reduced in the process where the fluid expands in the gas-liquid two-phase state. The volume change rate of 72) can be increased.

Therefore, according to the first embodiment, the volume change rate of the expansion chambers (71, 72) can be increased without increasing the number of turns of the fixed side wrap (63) or the movable side wrap (66). It can be made suitable for the process in which the refrigerant in the state becomes a saturated liquid, and it is possible to avoid an increase in the size of the expansion mechanism (60), and thus the compression / expansion unit (30). Further, according to the first embodiment, as compared with the conventional scroll fluid machine in which the volume change rate of the expansion chambers (71, 72) is constant, sufficient power can be obtained even in the process where the fluid in the supercritical pressure state becomes a saturated liquid. Recovery becomes possible. Further, according to the first embodiment, since the volume change rate of the expansion chambers (71, 72) can be changed according to the change in the characteristic of the expanding fluid, the torque fluctuation width of the rotational power obtained by the expansion of the fluid is reduced. it can.

[0089]

[Embodiment 2] In Embodiment 2 of the present invention, in the expansion mechanism portion (60) of Embodiment 1 described above, the shapes of the fixed side wrap (63) and the movable side wrap (66) are changed, and The first chamber (71) and the second chamber (72) differ in the closing completion time and the refrigerant outflow start time. In the second embodiment, as in the first embodiment, the volume change rate of the expansion chambers (71, 72) changes in accordance with the rotation angle of the orbiting scroll (64). Here, the differences of the expansion mechanism (60) of the second embodiment from the first embodiment will be described.

As shown in FIGS. 7 and 8, the fixed side wrap (63) and the movable side wrap (66) according to the second embodiment have an outer peripheral line and an inner peripheral line obtained by combining an arc and an involute curve. It is formed in the shape which becomes a thing. The thickness of the fixed-side wrap (63) and the movable-side wrap (66) increases and decreases in the extension direction. This is the same as in the first embodiment. However, the portions of the fixed side wrap (63) and the movable side wrap (66) of the second embodiment where the wall thickness is changed are different from those of the first embodiment.

As shown in FIG. 7, the fixed-side wrap (63) of the second embodiment has a shape extended by a winding angle of 180 ° in the direction of the outer peripheral end compared to that of the first embodiment. (See FIG. 3). The increase / decrease in the thickness of the fixed side wrap (63) will be described. Fixed side wrap (63)
Assuming that the wall thickness at the center side end and the outer peripheral side end is t ₀ , the wall thickness of the fixed side wrap (63) gradually increases in the portion where the winding angle is about 90 ° from the start of winding, and t ₁ Become.
Winding angle at a portion of about 90 ° to about 270 °, the thickness of the fixed side wrap (63) is kept in the t _1. The portion of the wrap angle of about 270 ° to about 360 °, back to t ₀ thickness gradually decreases and the fixed side wrap (63). Winding angle at a portion from about 360 ° to about 400 °, the thickness of the fixed side wrap (63) is kept at the t _0.

Subsequently, the winding angle is from about 400 ° to about 470.
The portion up °, the thickness of the fixed side wrap (63) becomes t ₂ decreases gradually. This portion constitutes a reduced thickness portion (81). Winding angle at a portion from about 470 ° to about 550 °, the thickness of the fixed side wrap (63) is kept in t _2. This portion constitutes a thin portion (82).
In the portion where the winding angle is from about 550 ° to about 640 °, the thickness of the fixed side wrap (63) gradually increases and returns to t ₀ .
This portion constitutes a thickened portion (83). Then, the winding angle at the portion to end of winding of about 640 °, the thickness of the fixed side wrap (63) is kept at the t _0.

As shown in FIG. 8, the movable side wrap (66) of the second embodiment has a shape which is shorter than that of the first embodiment by a winding angle of 90 ° toward the center side end. (See FIG. 3). The increase or decrease in the thickness of the movable wrap (66) will be described. Assuming that the thickness of the movable side wrap (66) at the center end portion and the outer peripheral end portion is t ₀ , the thickness of the movable side wrap (66) gradually increases in a portion where the winding angle is about 90 ° from the start of winding. It increases to t ₃ .
The portion of the wrap angle of about 90 ° to about 110 °, the thickness of the movable side wrap (66) is kept in the t _3. In the part where the winding angle is from about 110 ° to about 190 °, the thickness of the movable wrap (66) gradually decreases and returns to t ₀ . The portion of the wrap angle of about 190 ° to about 340 °, the thickness of the movable side wrap (66) is kept at the t _0.

Subsequently, the winding angle is about 340 ° to about 460.
The portion up °, the thickness of the movable side wrap (66) is t ₄ gradually decreases. This portion constitutes a reduced thickness portion (81). The portion of the wrap angle of about 460 ° to about 490 °, the thickness of the movable side wrap (66) is kept at the t _4. This portion constitutes a thin portion (82).
In the portion where the winding angle is from about 490 ° to about 650 °, the thickness of the movable wrap (66) gradually increases and returns to t ₀ .
This portion constitutes a thickened portion (83). Then, the winding angle at the portion to end of winding of about 650 °, the thickness of the movable side wrap (66) is kept at the t _0.

As shown in FIG. 9, by engaging the fixed-side wrap (63) and the movable-side wrap (66) having the above-mentioned predetermined shapes, the first expansion chamber (71) and the second expansion chamber (71) are brought into contact with each other. The second chamber (72), which is an expansion chamber, is partitioned and formed as a pair.
When the fixed wrap (63) and the movable wrap (66) are engaged with each other, the outer peripheral end of the fixed wrap (63) is located just outside the outer peripheral end of the movable wrap (66). positioned. Further, as described above, the movable wrap (66)
By shortening the center-side end of the first chamber (71), the closing completion time of the first chamber (71) is delayed later than the closing completion time of the second chamber (72), and the first chamber (71) and the second chamber are closed. The expansion ratio of (72) is made to match each other.

-Operation-The operation of the expansion mechanism (60) according to the second embodiment will be described below, focusing on differences from the first embodiment. Here, description will be made with reference to FIGS. 9 and 10. When the movable wrap (66) is at the position shown in FIG. 9, the closing of the first chamber (71) is completed in the innermost peripheral portions of the fixed wrap (63) and the movable wrap (66). In contrast, the second chamber (72) is still in communication with the inflow port (69).

[0097] When the movable scroll (64) slide into revolve counterclockwise in FIG. 9, as shown in FIG. 10, the second chamber when the rotation angle of the movable scroll (64) becomes T ₁ (7
2) is shut off from the inflow port (69), and the closing of the second chamber (72) is completed. Then, the second room (7
In 2), the refrigerant expands and the internal pressure of the second chamber (72) decreases as the orbiting scroll (64) rotates.

[0098] pressure drop in the second chamber (72) continues until the rotation angle of the movable scroll (64) is T _3. Then, the movable scroll (64) of the rotation angle is T ₃ and became point in the second chamber (72) communicates with the outlet (70), the second chamber (7
The refrigerant flows out from 2) to the outlet (70).

[0099] On the other hand, the first chamber (71), at the time when the rotation angle of the movable scroll (64) becomes T _1, communicates with the still inlet (69) (see FIG. 9). And
After that first chamber (71) continues to flow refrigerant into the first chamber at the time when the rotation angle of the movable scroll (64) becomes T ₂ (71)
Is completed. After that, the first closed space
The refrigerant expands in the chamber (71), and the movable scroll (64)
The internal pressure of the first chamber (71) decreases as the cylinder rotates.

[0100] inner pressure reduction in the first chamber (71) continues until the rotation angle of the movable scroll (64) is T _4. That is, even at the time when the rotation angle of the movable scroll (64) starts to flow out the refrigerant from the second chamber becomes T ₃ (72), the first chamber (71) in still expansion of the refrigerant is continued.
The communicating rotational angle first chamber at the time point when T ₄ (71) outlet (70) of the movable scroll (64), the refrigerant to the outlet (70) from the first chamber (71) flows out I do.

As described above, in the second embodiment, the closing completion time of the first chamber (71) is later than the closing completion time of the second chamber (72). The timing at which the refrigerant starts flowing out of the second chamber (72) is later than the timing at which the refrigerant starts flowing out of the second chamber (72). Therefore, at any time up to the rotation angle of the movable scroll (64) reaches from T ₁ to T _4, the direction of the internal pressure of the first chamber (71) a second chamber (7
2) Internal pressure is higher. In addition, the first room (71)
And the expansion ratio of the second chamber (72) is equal to the pressure of the refrigerant flowing out of the first chamber (71) and the refrigerant flowing out of the second chamber (72), as shown in FIG. Has the same value as the pressure.

-Effects of Second Embodiment- In the expansion mechanism (60) according to the second embodiment, the closing completion timing of the paired first chamber (71) and second chamber (72) is determined. The start time of the refrigerant is different from the start time. Therefore, according to the second embodiment, the fluctuation range of the rotational force applied to the movable scroll (64) by the expansion of the refrigerant in the first chamber (71) and the second chamber (72) can be reduced, and the expansion mechanism (60) The torque fluctuation width of the rotating power obtained in (60) can be reduced. That is, according to the second embodiment, in addition to changing the volume change rate of the first chamber (71) and the second chamber (72), the torque fluctuation width of the rotational power obtained in the expansion mechanism (60) is reduced. The size can be further reduced.

The expansion mechanism (6) according to the second embodiment
In (0), the first chamber (71) and the second chamber (72) have different closing completion timings, and the first chamber (71) and the second chamber
The flow rate of the refrigerant flowing through the inflow port (69) is lower than that in which the chamber (72) completes the closing at the same time. Therefore, the pressure loss of the refrigerant when passing through the inflow port (69) can be reduced, and the pressure of the fluid flowing into the first chamber (71) and the second chamber (72) can be maintained high. . Therefore, according to the second embodiment, sufficient pressure difference of the refrigerant in the inlet and outlet ports of the expansion mechanism (60) can be secured, the rotational power W _E extractable in the expansion mechanism (60) can be increased.
As a result, it is possible to the motor (40) by reducing the rotational power W _C to be imparted to the compression mechanism (50) by reducing the power consumption of the air conditioner (10), improving the COP of the air conditioner (10) Can be done.

Further, the inflation mechanism (6
In (0), the outer peripheral end of the fixed wrap (63) is located near the outer peripheral end of the movable wrap (66). Therefore, both the refrigerant flowing out of the first chamber (71) and the refrigerant flowing out of the second chamber (72) flow into the outlet (70) immediately after flowing out, and are compressed and discharged from the outlet port (37). It is sent out of the expansion unit (30). For this reason, the outflowing refrigerant flows before reaching the outlet (70) as compared with the conventional case where the outflow point of the refrigerant is 180 ° apart between the first chamber (71) and the second chamber (72). The distance can be shortened, and the amount of heat absorbed by the refrigerant during the distance can be reduced.

Here, the cooling capacity of the air conditioner (10) is as follows:
This is a value obtained by multiplying the enthalpy difference between the points a and e in FIG. 5 by the refrigerant circulation amount. On the other hand, when the enthalpy of the refrigerant flowing out of the expansion mechanism (60) increases, the point e moves to the right in FIG. 5, and the enthalpy difference between the points a and e decreases. On the other hand, according to the second embodiment, it is possible to prevent the enthalpy of the refrigerant flowing out of the expansion mechanism (60) from rising, thereby sufficiently securing the cooling capacity of the air conditioner (10). it can.

-Variation of Embodiment 2- In Embodiment 2, the shape of the center side end of the movable wrap (66) is changed so that the closing completion time of the first chamber (71) is changed to the second time. The first chamber (71) and the second chamber (72) are made to have the same expansion ratio while delaying the closing time of the chamber (72). On the other hand, as shown in FIG. 11, the shape of the inlet (69) is changed without changing the center-side end of the movable-side wrap (66), so that the first chamber (71) and the second chamber (71) are not changed.
The closing completion time of the chamber (72) may be shifted, and the expansion rates of the two may be matched.

In this case, the inflow port (69) opens slightly horizontally along the center-side end of the fixed-side wrap (63). Then, even if the outer side surface of the center side end of the movable side wrap (66) is in contact with the inner side surface of the center side end of the fixed side wrap (63) as shown in FIG. Communicates with the inflow port (69), and the refrigerant continues to flow into the first chamber (71). For this reason, the closing completion time of the first chamber (71) is
It is later than the closing completion time of the chamber (72), and the expansion ratios of the first chamber (71) and the second chamber (72) match.

[0108]

Other Embodiments of the Invention-First Modification-In each of the above embodiments, the shape of the fixed wrap (63) and the movable wrap (66) is such that the outer peripheral line and the inner peripheral line are arcs. The shape is such that the involute curve and the involute curve are drawn alternately, thereby changing the thickness of the fixed-side wrap (63) and the movable-side wrap (66). On the other hand, fixed side wrap (63)
And the movable wrap (66) are formed in an involute curve over the entire length, and the base circle radius of the involute curve is increased or decreased in accordance with the extension angle, so that the fixed wrap (63) and the movable wrap ( The thickness of 66) may be changed.

Here, when the wrap (63, 66) is formed in the form of an involute curve over its entire length, the wrap (63, 66) is increased by increasing the base circle radius as the extension angle of the involute curve increases. ) Gradually increases in thickness, and conversely, as the extension angle of the involute curve increases, the thickness of the wrap (63, 66) gradually decreases as the base circle radius decreases. This is described in, for example,
It is also disclosed in JP-A-252102.

When the volume change rate of the expansion chamber (71, 72) is changed as in each of the above embodiments, the base circle radius is reduced until the extension angle of the involute curve reaches a predetermined value. When the extension angle of the involute curve exceeds a predetermined value, the wrap (63, 66) is formed in a predetermined shape by increasing the base circle radius. At this time, the thickness of the wrap (63, 66) continuously decreases until the extension angle of the involute curve reaches a predetermined value, and continuously increases after the extension angle exceeds the predetermined value. . That is,
The wrap (63, 66) of the present modified example is formed with a wall thickness decreasing part whose wall thickness gradually decreases and a wall thickness increasing part whose wall thickness gradually increases.

Second Modification In each of the above embodiments, the air conditioner (10) is configured by using the refrigeration apparatus according to the present invention, but instead of this, a water heater for generating hot water is used. May be configured. In this case, in the refrigerant circuit (20), a heating heat exchanger for exchanging heat between the refrigerant and water is provided in place of the indoor heat exchanger (24).
The four-way switching valve (21) and the second four-way switching valve (22) are omitted. Then, the refrigerant discharged from the compression mechanism (50) is sent to the heat exchanger for heating, and water is heated by heat radiation from the refrigerant. In addition, the refrigerant after heat release is supplied to the expansion mechanism (6
After being expanded at 0), it is sent to the outdoor heat exchanger (23), and after absorbing heat from outdoor air, is sucked again into the compression mechanism (50).

[Brief description of the drawings]

FIG. 1 is a piping diagram of an air conditioner according to a first embodiment.

FIG. 2 is a schematic sectional view of a compression / expansion unit according to the first embodiment.

FIG. 3 is a sectional view taken along the line AA of FIG. 2, showing the shapes of a fixed side wrap and a movable side wrap according to the first embodiment.

FIG. 4 is a plan view showing a shape of a fixed-side wrap according to the first embodiment.

FIG. 5 is a Mollier chart showing a refrigeration cycle of the air conditioner according to the first embodiment.

FIG. 6 is a diagram illustrating a relationship between a rotation angle of a movable scroll and a projected area of the expansion chamber, showing a change in a volume change rate of the expansion chamber in the expansion mechanism unit according to the first embodiment.

FIG. 7 is a plan view showing a shape of a fixed-side wrap according to a second embodiment.

FIG. 8 is a plan view showing a shape of a movable side wrap according to a second embodiment.

FIG. 9 is a diagram corresponding to FIG. 3, showing the shapes of a fixed side wrap and a movable side wrap according to the second embodiment.

FIG. 10 is a diagram illustrating a relationship between a rotation angle of a movable scroll and internal pressures of a first chamber and a second chamber in an expansion mechanism according to a second embodiment.

FIG. 11 is a view corresponding to FIG. 3 showing shapes of a fixed side wrap and a movable side wrap according to a modification of the second embodiment.

FIG. 12 is a schematic cross-sectional view showing shapes of a fixed side wrap and a movable side wrap according to the related art.

FIG. 13 is a relationship diagram between pressure and specific volume when carbon dioxide is expanded from a supercritical pressure state to a gas-liquid two-phase state.

[Explanation of symbols]

 (20) Refrigerant circuit (50) Compression mechanism (compressor) (60) Expansion mechanism (scroll fluid machine) (61) Fixed scroll (64) Movable scroll (63) Fixed wrap (66) Movable wrap (66) 69) Inflow port (71) First chamber (first expansion chamber) (72) Second chamber (second expansion chamber) (81) Wall thickness reduction part (82) Thin wall part (83) Wall thickness increase part

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kazuhiro Furusho 1304 Kanaokacho, Sakai-shi, Osaka Daikin Industries, Ltd. Sakai Seisakusho Kanaoka Factory F-term (reference) 3H029 AA02 AA14 AB03 BB23 BB31 BB43 CC03 CC04 CC19 3H039 AA03 AA06 AA12 BB01 BB07 BB28 CC02 CC03 CC04 CC05

Claims (10)

[Claims] A spiral wrap (63, 66) for each.
Are provided with a fixed scroll (61) and a movable scroll (64), and the wraps (63, 66) of the fixed scroll (61) and the movable scroll (64) are engaged with each other to expand the expansion chambers (71, 72). Is formed in the scroll-type fluid machine, wherein a fluid having a supercritical pressure flows into the expansion chambers (71, 72), and the fluid expands into a gas-liquid two-phase state to form the expansion chambers (71, 72). 72)
On the other hand, while the expansion chambers (71, 72) are closed spaces, the volume of the expansion chambers (71, 72) is not increased until the rotation angle of the movable scroll (64) reaches a predetermined value. When the rotation angle of the orbiting scroll (64) exceeds the predetermined value, the volume of the expansion chamber (71, 72) increases at a second rate of change, and the first rate of change increases. A scroll type fluid machine configured to be smaller than the second rate of change. 2. The scroll-type fluid machine according to claim 1, wherein the volume change rate of the expansion chamber (71, 72) is equal to the movable scroll (64).
A scroll-type fluid machine in which the thickness of the wrap (63, 66) is changed so that the wrap (63, 66) changes from the first rate of change to the second rate of change with the rotation of. 3. The scroll-type fluid machine according to claim 2, wherein the wraps (63, 66) are wrapped in an extending direction from the center end to the outer end of the wrap (63, 66). A thickness-reduced portion in which the thickness of the (63, 66) is gradually reduced; and a thickness in which the thickness of the wrap (63, 66) is gradually increased as the wrap (63, 66) proceeds in the extension direction and continues to the end of the thickness-reduced portion. A scroll-type fluid machine having an enlarged portion. 4. The scroll-type fluid machine according to claim 2, wherein the wraps (63, 66) are wrapped in the extending direction from the center end to the outer end of the wrap (63, 66). And a lap (63, 66) continuous with the end of the reduced thickness portion (81), where the thickness of the (63, 66) is gradually reduced.
6) a thin portion (82) in which the thickness of the wrap (63, 66) is kept constant, and the thickness of the wrap (63, 66) gradually increases as the wrap (63, 66) advances in the extension direction. A scroll type fluid machine in which a thickness increasing portion (83) is formed. 5. The scroll type fluid machine according to claim 2, wherein the wrap (63, 66) is formed in an involute curve over the entire length of the wrap (63, 66). 66. A scroll-type fluid machine in which the thickness of the wrap (63, 66) is changed by increasing or decreasing the base circle radius of the involute curve representing the shape of (66) in accordance with the opening angle of the involute curve. 6. The scroll-type fluid machine according to claim 2, wherein an involute curved portion and an arc-shaped portion are alternately formed on an inner surface and an outer surface of the wrap (63, 66). A scroll type fluid machine that changes the thickness of the wrap (63, 66). 7. The scroll-type fluid machine according to claim 1, wherein the expansion chambers (71, 72) are formed by a first expansion chamber (71) and a second expansion chamber (72). The closing completion timing of the first expansion chamber (71) is determined by the second expansion chamber (71).
Is delayed from the time when the closing of the expansion chamber (72) is completed, and the time when the fluid starts flowing out of the first expansion chamber (71) is the time when the fluid starts flowing out of the second expansion chamber (72). A scroll type fluid machine that has been delayed from its timing. 8. The scroll type fluid machine according to claim 7, wherein an expansion ratio in the first expansion chamber (71) and a second expansion chamber (7) are different from each other.
A scroll-type fluid machine configured to have the same expansion ratio as in 2). 9. The scroll type fluid machine according to claim 7, wherein one of the wrap (63) of the fixed scroll (61) and the movable scroll (64) is an outer peripheral side of the other wrap (66). A scroll-type fluid machine that extends to near the end. 10. A refrigerant circuit in which the scroll type fluid machine (60) according to any one of claims 1 to 9 is connected to a refrigerant compressor (50), and the refrigerant circuit is filled with carbon dioxide as a refrigerant. When performing a refrigeration cycle by circulating a refrigerant in the refrigerant circuit (20), the refrigerant is compressed by the compressor (50) to a pressure higher than the critical pressure of the refrigerant, and A refrigeration system that uses the power recovered by expanding the swelling fluid in the scroll fluid machine (60) to drive the compressor (50).