JP5103952B2 - Refrigeration equipment - Google Patents

Description

  The present invention relates to a method of supplying lubricating oil to an expander in a refrigeration apparatus including a compressor and an expander.

  2. Description of the Related Art Conventionally, refrigeration apparatuses that perform a refrigeration cycle by circulating refrigerant in a refrigerant circuit are widely used for applications such as air conditioners. For example, Patent Document 1 discloses a refrigeration apparatus including a compressor that compresses a refrigerant and a power recovery expander that expands the refrigerant. Specifically, in the refrigeration apparatus described in FIG. 1 of Patent Document 1, the expander is connected to the compressor by a single shaft, and the power obtained by the expander is used to drive the compressor. Moreover, in the refrigeration apparatus described in FIG. 6 of Patent Document 1, an electric motor is connected to the compressor, and a generator is connected to the expander. In this refrigeration apparatus, a compressor is driven by an electric motor to compress refrigerant, while a generator is driven by an expander to generate electric power.

  For example, Patent Document 2 discloses a fluid machine in which an expander and a compressor are connected by a single shaft. In the fluid machine disclosed in this patent document, a compression mechanism as a compressor, an expansion mechanism as an expander, and a shaft for connecting both are housed in one casing. Further, in this fluid machine, an oil supply passage is formed inside the shaft, and the lubricating oil accumulated at the bottom of the casing is supplied to the compression mechanism and the expansion mechanism through the oil supply passage.

Patent Document 3 discloses a so-called hermetic compressor. In this hermetic compressor, the compression mechanism and the electric motor are accommodated in one casing. Further, in this hermetic compressor, an oil supply passage is formed in the drive shaft of the compression mechanism, and lubricating oil accumulated at the bottom of the casing is supplied to the compression mechanism through the oil supply passage.
Japanese Patent Laid-Open No. 2000-241033 JP 2005-299632 A JP 2005-002832 A

  In a refrigeration apparatus in which a compressor and an expander that are separate from each other as disclosed in Patent Document 1 are connected to a refrigerant circuit, a hermetic compressor as disclosed in Patent Document 3 can be used. . In that case, in the compressor, lubrication of the compression mechanism is performed using the lubricating oil accumulated in the casing.

  By the way, the expansion mechanism of an expander is comprised with a fluid machine similarly to the compression mechanism of a compressor. For this reason, the expansion mechanism also needs to be lubricated with lubricating oil, like the compression mechanism. Conventionally, however, no specific study has been made on how to supply the lubricating oil to the expansion mechanism of the expander.

  The present invention has been made in view of such points, and an object of the present invention is to reliably supply lubricating oil to each of the compressor and the expander in a refrigeration apparatus including the compressor and the expander formed separately. Thus, the reliability of the refrigeration apparatus is ensured.

The first invention is directed to a refrigeration apparatus including a refrigerant circuit (11) to which a compressor (20) and an expander (30) are connected, and performing a refrigeration cycle by circulating refrigerant in the refrigerant circuit (11). And The compressor (20) includes an airtight container-like compressor casing (24) to which a suction pipe (25) is attached , and is accommodated in the compressor casing (24) and from the suction pipe (25). A compression mechanism (21) that compresses the sucked refrigerant and discharges it into the compressor casing (24), and supplies the lubricating oil stored in the compressor casing (24) to the compression mechanism (21). configured to, the expander (30), and the expansion mechanism (31) for expanding the refrigerant flowing into generating power by a expander casing (34) housing the expansion mechanism (31), the An inflow pipe (35) that penetrates the expander casing (34) and is connected to the expansion mechanism (31) to introduce the refrigerant into the expansion mechanism (31); penetrates the expander casing (34) and A flow that is connected to the expansion mechanism (31) and draws the refrigerant from the expansion mechanism (31) And an oil return pipe (42) for introducing lubricating oil accumulated in the expander casing (34) into the suction pipe (25) of the compressor (20). One end is connected to the bottom of the compressor casing (24), the other end is connected to the expansion mechanism (31) through the expander casing (34 ), and is stored in the compressor casing (24). An oil supply pipe (41) for supplying the lubricated oil to the expansion mechanism (31) is provided. In the expansion mechanism (31), the inflow pipe (35) communicates with the fluid chamber (72) in which the refrigerant expands. The oil supply pipe (41) communicates with the oil passage (111, 112, 113) through which the lubricating oil flows, and the expansion mechanism (31) is lubricated by the lubricating oil supplied through the oil supply pipe (41). It is.

  In the first invention, the refrigeration cycle is performed by circulating the refrigerant in the refrigerant circuit (11). In the compressor (20), the compression mechanism (21) compresses the sucked refrigerant and discharges the compressed refrigerant to the internal space of the compressor casing (24). The high-pressure refrigerant derived from the compressor casing (24) radiates heat to an object such as air or water, and then flows into the expansion mechanism (31) of the expander (30) and expands. In the expansion mechanism (31), power is recovered from the high-pressure refrigerant that has flowed. The refrigerant expanded by the expansion mechanism (31) absorbs heat from an object such as air or water and is then sucked into the compression mechanism (21) of the compressor (20).

In the compressor casing (24) of the first invention, the internal pressure becomes equal to the pressure of the refrigerant immediately after being discharged from the compression mechanism (21), and lubricating oil is stored in the internal space. The lubricating oil stored in the compressor casing (24) is supplied to the compression mechanism (21) and used for lubrication of the compression mechanism (21). The lubricating oil stored in the compressor casing (24) is also supplied to the expansion mechanism (31) through the oil supply pipe (41) and used for lubrication of the expansion mechanism (31).

In the oil supply pipe of the first aspect of the invention (41), the lubricating oil flows in the compressor casing (24) at one end thereof, the inflow lubricating oil flows toward the other end. The lubricating oil flowing through the oil supply pipe (41 ) is introduced from the other end of the oil supply pipe (41) into the oil passages (111 to 113) of the expansion mechanism (31).

In the first invention, the refrigeration apparatus is provided with the oil return passage (42). In the expander (30), part of the lubricating oil supplied to the expansion mechanism (31) through the oil supply pipe (41) flows out of the expander (30) together with the refrigerant passing through the expansion mechanism (31). However, the remainder leaks from the expansion mechanism (31) and accumulates in the expander casing (34). The lubricating oil accumulated in the expander casing (34) is sent back to the compressor (20) through the oil return passage (42).

In the first invention, the lubricating oil accumulated in the expander casing (34) flows into the suction pipe (25) of the compression mechanism (21) through the oil return passage (42) and is compressed together with the low-pressure refrigerant ( 21) is inhaled. The lubricating oil sucked into the compression mechanism (21) together with the refrigerant is discharged together with the compressed refrigerant from the compression mechanism (21) to the internal space of the compressor casing (24).

A second invention is the cooling heat exchanger according to the first invention, wherein the lubricating oil flowing through the oil supply pipe (41) is cooled by exchanging heat with the refrigerant sucked into the compression mechanism (21). (46) is provided.

In the second invention, a cooling heat exchanger (46) is provided in the refrigeration apparatus. In the cooling heat exchanger (46), the lubricating oil flowing through the oil supply pipe (41) and the refrigerant sucked into the compression mechanism (21) exchange heat with each other. The refrigerant sucked into the compression mechanism (21) is at a lower temperature than the lubricating oil flowing through the oil supply pipe (41). For this reason, in the cooling heat exchanger (46), the lubricating oil flowing through the oil supply pipe (41) is cooled.

According to a third aspect of the present invention, in the first aspect of the invention, the cooling heat exchanger for cooling the lubricating oil flowing through the oil supply pipe (41) by exchanging heat with the lubricating oil flowing through the oil return passage (42). (47).

In the third invention, the refrigeration apparatus is provided with a cooling heat exchanger (47). In the cooling heat exchanger (47), the lubricating oil flowing through the oil supply pipe (41) and the lubricating oil flowing through the oil return passage (42) exchange heat with each other. The lubricating oil flowing through the oil return passage (42) is at a lower temperature than the lubricating oil flowing through the oil supply pipe (41). For this reason, in the cooling heat exchanger (47), the lubricating oil flowing through the oil supply pipe (41) is cooled.

According to a fourth invention, in the first invention, a cooling heat exchanger (48) for cooling the lubricating oil flowing through the oil supply pipe (41) by exchanging heat with outdoor air is provided.

In the fourth invention, the refrigeration apparatus is provided with a cooling heat exchanger (48). In the cooling heat exchanger (48), the lubricating oil flowing through the oil supply pipe (41) and the outdoor air exchange heat with each other. The outdoor air has a lower temperature than the lubricating oil flowing through the oil supply pipe (41). For this reason, in the cooling heat exchanger (48), the lubricating oil flowing through the oil supply pipe (41) is cooled.

According to a fifth invention, in any one of the first to fourth inventions, the refrigerant circuit (11) includes an evaporator of the refrigerant circuit (11) and an internal space of the expander casing (34). A first suction-side passage (17) that communicates with each other, and a second suction-side passage (18) that communicates the internal space of the expander casing (34) with the suction side of the compression mechanism (21). The expander casing (34) separates the refrigerant flowing from the first suction side passage (17) into a gas refrigerant and a liquid refrigerant and sends the gas refrigerant to the second suction side passage (18). It is composed.

In the fifth invention, the refrigerant circuit (11) is provided with the first suction side passage (17) and the second suction side passage (18). In this refrigerant circuit (11), the low-pressure refrigerant flowing out of the evaporator flows into the internal space of the expander casing (34) through the first suction side passage (17). The refrigerant flowing into the internal space of the expander casing (34) is sucked into the compression mechanism (21) through the second suction side passage (18). That is, in the refrigerant circuit (11) of the present invention, the refrigerant flowing out of the evaporator passes through the internal space of the expander casing (34) and then is sucked into the compression mechanism (21) of the compressor (20).

  Here, in the evaporator of the refrigerant circuit (11), the refrigerant that has flowed in may not completely evaporate, and some of the refrigerant may flow out of the evaporator while remaining as liquid refrigerant. In such a case, if the amount of the liquid refrigerant flowing out of the evaporator is large, the liquid refrigerant may be sucked into the compression mechanism (21) and cause the compression mechanism (21) to be damaged.

In contrast, in the fifth aspect of the present invention, even if a gas-liquid two-phase refrigerant flows from the first suction side passage (17) into the internal space of the expander casing (34), the refrigerant is a gas refrigerant and a liquid refrigerant. The gas refrigerant passes through the second suction side passage (18) and is sent to the compression mechanism (21). That is, the expander casing (34) of the present invention functions as a so-called accumulator.

In a sixth aspect based on the fifth aspect , the expander (30) includes a generator (33) housed in the expander casing (34) and driven by the expansion mechanism (31). In the inner space of the expander casing (34), the first suction side passage (17) communicates with the lower part of the generator (33), and the upper part of the generator (33) The second suction side passage (18) is in communication.

In the sixth invention, the generator (33) is accommodated in the expander casing (34). The generator (33) is driven by the expansion mechanism (31) to generate power. In this invention, the low-pressure refrigerant flowing into the internal space of the expander casing (34) through the first suction side passage (17) passes through the generator (33) from the bottom to the second suction. It flows into the side passage (18). When the refrigerant flowing into the expander casing (34) from the first suction side passage (17) is in a gas-liquid two-phase state, the gas refrigerant passes through the generator (33) to the second suction side passage (18). While flowing in, the liquid refrigerant adheres to the generator (33) and then flows down toward the bottom of the expander casing (34).

  In the present invention, lubricating oil is stored in the compressor casing (24) whose internal pressure is equal to the pressure of the refrigerant immediately after being discharged from the compression mechanism (21), and the lubricating oil is stored in the compression mechanism (21) and the expansion mechanism (31). Supply to both. In other words, in the present invention, the lubricating oil is stored in the part having the highest pressure in the refrigerant circuit (11), and the lubricating oil is compressed into the compression mechanism (21 having a lower part than the internal pressure of the compressor casing (24). ) And expansion mechanism (31). For this reason, the supply source of the lubricating oil has a higher pressure than the supply destination, and the lubricating oil is reliably supplied to the compression mechanism (21) and the expansion mechanism (31). Therefore, according to the present invention, the amount of lubricating oil supplied to the compression mechanism (21) and the expansion mechanism (31) can be secured, and troubles such as seizure of the compression mechanism (21) and the expansion mechanism (31) can be prevented. Therefore, the reliability of the refrigeration apparatus can be ensured.

In the present invention , the lubricating oil accumulated in the expander casing (34) is returned to the compressor (20) through the oil return passage (42). Since the amount of lubricating oil present in the refrigerant circuit (11) is constant, if the amount of lubricating oil accumulated in the expander casing (34) increases, the amount of lubricating oil in the compressor casing (24) increases accordingly. The amount of storage is reduced, and there is a possibility that the lubricating oil may not be sufficiently supplied to the compression mechanism (21) and the expansion mechanism (31). On the other hand, in the present invention , the lubricating oil in the expander casing (34) is sent back to the compression mechanism (21) through the oil return passage (42). Therefore, according to the present invention , a sufficient amount of lubricating oil can be secured in the compressor casing (24), and the lubricating oil can be more reliably supplied to the compression mechanism (21) and the expansion mechanism (31). Can do.

In the present invention , the lubricating oil collected in the expander casing (34) is sent to the suction side of the compression mechanism (21). The suction side of the compression mechanism (21) is the part having the lowest pressure in the refrigerant circuit (11). In other words, in the present invention , a pressure difference can be reliably generated between the internal space of the expander casing (34) in which the lubricating oil accumulates and the return destination of the lubricating oil. Therefore, according to the present invention , the lubricating oil accumulated in the expander casing (34) can be reliably sent back to the compressor (20), and the amount of lubricating oil stored in the compressor casing (24) is ensured. be able to.

  Incidentally, the lubricating oil and the refrigerant discharged from the compression mechanism (21) coexist in the internal space of the compressor casing (24). For this reason, the temperature of the lubricating oil stored in the compressor casing (24) is approximately the same as the temperature of the refrigerant discharged from the compression mechanism (21). The refrigerant immediately after being discharged from the compression mechanism (21) has the highest temperature among the refrigerants circulating in the refrigerant circuit (11). For this reason, when the high-temperature lubricating oil stored in the compressor casing (24) is supplied to the expansion mechanism (31) as it is, the refrigerant passing through the expansion mechanism (31) is heated by the lubricating oil, and the expansion mechanism (31) The enthalpy of the refrigerant flowing out from the refrigerant increases. When the enthalpy of the refrigerant flowing out from the expansion mechanism (31) increases, the amount of heat that the expanded refrigerant absorbs heat from air, water, or the like may decrease, leading to a decrease in the capacity of the refrigeration apparatus.

On the other hand, in each of the second, third, and fourth inventions , the lubricating oil that flows out of the compressor casing (24) and flows through the oil supply pipe (41) is supplied to the cooling heat exchanger (46, 47, 48). ) And then supplied to the expansion mechanism (31). For this reason, compared with the case where the lubricating oil stored in the compressor casing (24) is directly introduced into the expansion mechanism (31), the lubricating oil supplied through the oil supply pipe (41) passes through the expansion mechanism (31). The amount of heat entering the refrigerant can be reduced. Therefore, according to these inventions, the enthalpy of the refrigerant flowing out from the expansion mechanism (31) can be suppressed to a low level, and the capacity reduction of the refrigeration apparatus can be suppressed.

In particular, according to the second aspect of the invention, the refrigerant flowing through the refueling pipe (41) and the refrigerant sucked into the compression mechanism (21) (that is, the coldest refrigerant among the refrigerant circulating in the refrigerant circuit (11)). Heat exchange with oil. Therefore, according to the present invention, the temperature of the lubricating oil introduced into the expansion mechanism (31) through the oil supply pipe (41) can be reliably reduced, and the capacity reduction of the refrigeration apparatus can be more reliably suppressed. .

In the fifth aspect , the expander casing (34) also functions as an accumulator for separating the liquid refrigerant from the refrigerant sucked into the compressor (20). For this reason, it is not necessary to separately provide an accumulator in the refrigerant circuit (11), and the configuration of the refrigeration apparatus can be simplified by reducing the components of the refrigerant circuit (11).

In the sixth aspect of the invention, the refrigerant flowing into the expander casing (34) from the first suction side passage (17) flows into the second suction side passage (18) after passing through the generator (33). For this reason, even when the refrigerant flowing into the expander casing (34) from the first suction side passage (17) is in a gas-liquid two-phase state, the refrigerant flowing into the second suction side passage (18) is almost a gas refrigerant. It becomes only. Therefore, according to the present invention, damage to the compression mechanism (21) due to suction of the liquid refrigerant can be avoided reliably, and the reliability of the compressor (20) can be ensured.

In the sixth aspect of the invention, since the refrigerant passes through the generator (33), the generator (33) is cooled by the refrigerant. Therefore, according to this invention, the temperature rise of the generator (33) can be suppressed, and the efficiency of the generator (33) can be improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Embodiment 1 of the Invention
A first embodiment of the present invention will be described. The present embodiment is an air conditioner (10) configured by a refrigeration apparatus according to the present invention.

<Overall configuration of air conditioner>
As shown in FIG. 1, the air conditioner (10) of this embodiment includes a refrigerant circuit (11). The refrigerant circuit (11) includes a compressor (20), an expander (30), an outdoor heat exchanger (14), an indoor heat exchanger (15), a first four-way switching valve (12), The second four-way switching valve (13) is connected. The refrigerant circuit (11) is filled with carbon dioxide (CO ₂ ) as a refrigerant. The refrigerant circuit (11) is provided with an oil supply pipe (41), an oil return pipe (42), and a cooling heat exchanger (46).

  The configuration of the refrigerant circuit (11) will be described. The compressor (20) has its discharge pipe (26) connected to the first port of the first four-way switching valve (12) and its suction pipe (25) connected to the second port of the first four-way switching valve (12). Connected to the port. The expander (30) has an outflow pipe (36) connected to the first port of the second four-way switching valve (13) and an inflow pipe (35) connected to the second port of the second four-way switching valve (13). Connected to the port. One end of the outdoor heat exchanger (14) is connected to the third port of the first four-way switching valve (12), and the other end is connected to the fourth port of the second four-way switching valve (13). . The indoor heat exchanger (15) has one end connected to the third port of the second four-way switching valve (13) and the other end connected to the fourth port of the first four-way switching valve (12). . In the refrigerant circuit (11), a pipe connecting the suction pipe (25) of the compressor (20) and the second port of the first four-way switching valve (12) constitutes a suction side pipe (16).

The outdoor heat exchanger (14) is an air heat exchanger for exchanging heat between the refrigerant and outdoor air. The indoor heat exchanger (15) is an air heat exchanger for exchanging heat between the refrigerant and room air. The first four-way switching valve (12) and the second four-way switching valve (13) are respectively in a first state in which the first port and the third port communicate with each other and the second port and the fourth port communicate with each other. 1 (state shown by a solid line in FIG. 1) and a second state (state shown by a broken line in FIG. 1 ) in which the first port communicates with the fourth port and the second port communicates with the third port . It is comprised so that it may replace.

  The compressor (20) is a so-called high pressure dome type hermetic compressor. The compressor (20) includes a compressor casing (24) formed in a vertically long cylindrical shape. A compressor mechanism (21), an electric motor (23), and a drive shaft (22) are accommodated in the compressor casing (24). The compression mechanism (21) constitutes a so-called rotary positive displacement fluid machine. In the compressor casing (24), the electric motor (23) is disposed above the compression mechanism (21). The drive shaft (22) is arranged in a posture extending in the vertical direction, and connects the compression mechanism (21) and the electric motor (23).

  The compressor casing (24) is provided with a suction pipe (25) and a discharge pipe (26). The suction pipe (25) passes through the vicinity of the lower end of the body of the compressor casing (24), and its end is directly connected to the compression mechanism (21). The discharge pipe (26) passes through the top of the compressor casing (24), and the start end thereof opens into the space above the electric motor (23) in the compressor casing (24). The compression mechanism (21) compresses the refrigerant sucked from the suction pipe (25) and discharges it into the compressor casing (24).

  Refrigerating machine oil as lubricating oil is stored at the bottom of the compressor casing (24). In this embodiment, polyalkylene glycol (PAG) is used as the refrigerating machine oil. Although not shown, an oil supply passage extending in the axial direction is formed inside the drive shaft (22). The oil supply passage opens at the lower end of the drive shaft (22). The lower end of the drive shaft (22) is immersed in the oil sump (27). The refrigerating machine oil in the compressor casing (24) is supplied to the compression mechanism (21) through the oil supply passage of the drive shaft (22).

  The expander (30) includes an expander casing (34) formed in a vertically long cylindrical shape. An expansion mechanism (31), a generator (33), and an output shaft (32) are housed inside the expander casing (34). The expansion mechanism (31) constitutes a so-called rotary positive displacement fluid machine. Details of the expansion mechanism (31) will be described later. In the expander casing (34), a generator (33) is disposed below the expansion mechanism (31). The output shaft (32) is arranged in a posture extending in the vertical direction, and connects the expansion mechanism (31) and the generator (33).

  The expander casing (34) is provided with an inflow pipe (35) and an outflow pipe (36). Both the inflow pipe (35) and the outflow pipe (36) penetrate the vicinity of the upper end of the trunk portion of the expander casing (34). The end of the inflow pipe (35) is directly connected to the expansion mechanism (31). The starting end of the outflow pipe (36) is directly connected to the expansion mechanism (31). The expansion mechanism (31) expands the refrigerant that has flowed through the inflow pipe (35), and sends the expanded refrigerant to the outflow pipe (36). That is, the refrigerant passing through the expander (30) does not flow into the internal space of the expander casing (34) but passes only through the expansion mechanism (31).

  The oil supply pipe (41) has its start end connected to the compressor (20) and its end connected to the expander (30). Specifically, the start end of the oil supply pipe (41) passes through the bottom of the compressor casing (24) and opens into the internal space of the compressor casing (24). The starting end of the oil supply pipe (41) is immersed in the refrigeration oil accumulated at the bottom of the compressor casing (24), and is open to the same height as the lower end of the drive shaft (22). Yes. On the other hand, the terminal portion of the oil supply pipe (41) is directly connected to the expansion mechanism (31) in the expander casing (34). The connection position of the oil supply pipe (41) to the expansion mechanism (31) will be described later. The oil supply pipe (41) constitutes an oil supply passage. The refrigerating machine oil accumulated at the bottom of the compressor casing (24) is supplied to the expansion mechanism (31) through the oil supply pipe (41).

  The cooling heat exchanger (46) is connected to the oil supply pipe (41) and the suction side pipe (16). The cooling heat exchanger (46) exchanges heat between the refrigerating machine oil flowing through the oil supply pipe (41) and the refrigerant flowing through the suction side pipe (16).

  The oil return pipe (42) has a start end connected to the expander (30) and a terminal end connected to the suction side pipe (16). Specifically, the starting end of the oil return pipe (42) passes through the bottom of the expander casing (34) and opens into the internal space of the expander casing (34). The starting end of the oil return pipe (42) opens near the bottom of the expander casing (34). On the other hand, the terminal end of the oil return pipe (42) is connected to the downstream side of the cooling heat exchanger (46) in the suction pipe (16). In the expander (30), the refrigeration oil leaking from the expansion mechanism (31) accumulates in the expander casing (34). The refrigerating machine oil accumulated in the expander casing (34) is introduced into the suction side pipe (16) through the oil return pipe (42), and together with the refrigerant flowing through the suction side pipe (16), the compression mechanism (21) Inhaled.

<Configuration of expander>
The configuration of the expander (30) will be described in detail with reference to FIGS.

  As shown in FIG. 2, two eccentric portions (79, 89) are formed at the upper end portion of the output shaft (32). The two eccentric portions (79, 89) are formed to have a larger diameter than the main shaft portion (38) of the output shaft (32), the lower one is the first eccentric portion (79) and the upper one is The second eccentric portion (89) is configured. The first eccentric part (79) and the second eccentric part (89) are both eccentric in the same direction. The outer diameter of the second eccentric part (89) is larger than the outer diameter of the first eccentric part (79). The amount of eccentricity of the main shaft portion (38) with respect to the shaft center is larger in the second eccentric portion (89) than in the first eccentric portion (79).

  An oil supply passage (90) is formed in the output shaft (32). The oil supply passage (90) extends along the axis of the output shaft (32). One end of the oil supply passageway (90) opens to the upper end surface of the output shaft (32). The other end of the oil supply passageway (90) is bent at a right angle and extends in the radial direction of the output shaft (32). The outer periphery of the output shaft (32) is slightly lowered from the first eccentric portion (79). Open to the surface. Two branch passages (91, 92) extending in the radial direction of the output shaft (32) are formed in the oil supply passage (90). The first branch passage (91) opens to the outer peripheral surface of the first eccentric portion (79). The second branch passage (92) opens to the outer peripheral surface of the second eccentric portion (89).

  The expansion mechanism (31) is a so-called oscillating piston type rotary fluid machine. The expansion mechanism (31) is provided with two pairs of cylinders (71, 81) and pistons (75, 85) as a pair. The expansion mechanism (31) includes a front head (61), an intermediate plate (63), and a rear head (62).

  In the expansion mechanism (31), the front head (61), the first cylinder (71), the intermediate plate (63), the second cylinder (81), the rear head (62), the upper plate (65) are sequentially arranged from the bottom to the top. ) Are stacked. In this state, the first cylinder (71) has its lower end face closed by the front head (61) and its upper end face closed by the intermediate plate (63). On the other hand, the second cylinder (81) has its lower end face closed by the intermediate plate (63) and its upper end face closed by the rear head (62). The inner diameter of the second cylinder (81) is larger than the inner diameter of the first cylinder (71).

  The output shaft (32) passes through the stacked front head (61), first cylinder (71), intermediate plate (63), and second cylinder (81). The output shaft (32) has a first eccentric portion (79) located in the first cylinder (71) and a second eccentric portion (89) located in the second cylinder (81). .

  As shown in FIGS. 3 and 4, a first piston (75) is provided in the first cylinder (71), and a second piston (85) is provided in the second cylinder (81). The first and second pistons (75, 85) are both formed in an annular shape or a cylindrical shape. The outer diameter of the first piston (75) and the outer diameter of the second piston (85) are equal to each other. The inner diameter of the first piston (75) is approximately equal to the outer diameter of the first eccentric part (79), and the inner diameter of the second piston (85) is approximately equal to the outer diameter of the second eccentric part (89). The first eccentric portion (79) passes through the first piston (75), and the second eccentric portion (89) passes through the second piston (85).

  The first piston (75) has an outer peripheral surface in sliding contact with the inner peripheral surface of the first cylinder (71), one end surface in sliding contact with the front head (61), and the other end surface in contact with the intermediate plate (63). . A first fluid chamber (72) is formed in the first cylinder (71) between the inner peripheral surface thereof and the outer peripheral surface of the first piston (75). On the other hand, the outer peripheral surface of the second piston (85) is in sliding contact with the inner peripheral surface of the second cylinder (81), one end surface is in sliding contact with the rear head (62), and the other end surface is in sliding contact with the intermediate plate (63). ing. A second fluid chamber (82) is formed in the second cylinder (81) between the inner peripheral surface thereof and the outer peripheral surface of the second piston (85).

  One blade (76, 86) is provided integrally with each of the first and second pistons (75, 85). The blades (76, 86) are formed in a plate shape extending in the radial direction of the piston (75, 85), and protrude outward from the outer peripheral surface of the piston (75, 85). The blade (76) of the first piston (75) is in the bush hole (78) of the first cylinder (71), and the blade (86) of the second piston (85) is the bush hole (88) of the second cylinder (81). Are inserted respectively. The bush hole (78, 88) of each cylinder (71, 81) penetrates the cylinder (71, 81) in the thickness direction, and opens to the inner peripheral surface of the cylinder (71, 81).

  Each cylinder (71, 81) is provided with a pair of bushes (77, 87). Each bush (77, 87) is a small piece formed such that the inner surface is a flat surface and the outer surface is a circular arc surface. In each cylinder (71, 81), the pair of bushes (77, 87) are inserted into the bush holes (78, 88) and sandwich the blades (76, 86). Each bush (77, 87) has its inner side slidably in contact with the blade (76, 86) and its outer side slid with the cylinder (71, 81). The blade (76, 86) integral with the piston (75, 85) is supported by the cylinder (71, 81) via the bush (77, 87) and is rotatable with respect to the cylinder (71, 81). And you can move forward and backward.

  The first fluid chamber (72) in the first cylinder (71) is partitioned by a first blade (76) integral with the first piston (75), and the first blade (76) in FIGS. The left side is a first high pressure chamber (73) on the high pressure side, and the right side is a first low pressure chamber (74) on the low pressure side. The second fluid chamber (82) in the second cylinder (81) is partitioned by a second blade (86) integral with the second piston (85), and the second blade (86) in FIGS. The left side is a high pressure side second high pressure chamber (83), and the right side is a low pressure side second low pressure chamber (84).

The first cylinder (71) and the second cylinder (81) are arranged in a posture in which the positions of the bushes (77, 87) in the respective circumferential directions coincide. In other words, the arrangement angle of the second cylinder (81) with respect to the first cylinder (71) is 0 °. As described above, the first eccentric portion (79) and the second eccentric portion (89) are eccentric in the same direction with respect to the axis of the main shaft portion (38) . Accordingly, the first blade (76) is most retracted to the outside of the first cylinder (71), and the second blade (86) is most retracted to the outside of the second cylinder (81). .

  An inflow port (67) is formed in the first cylinder (71). The inflow port (67) opens at a position slightly on the left side of the bush (77) in FIGS. 3 and 4 in the inner peripheral surface of the first cylinder (71). The inflow port (67) can communicate with the first high pressure chamber (73). Although not shown, the inflow pipe (35) is connected to the inflow port (67).

  The second cylinder (81) has an outflow port (68). The outflow port (68) opens at a position slightly on the right side of the bush (87) in FIGS. 3 and 4 in the inner peripheral surface of the second cylinder (81). The outflow port (68) can communicate with the second low-pressure chamber (84). Although not shown, the outflow pipe (36) is connected to the outflow port (68).

A communication path (64) is formed in the intermediate plate (63). The communication path (64) penetrates the intermediate plate (63) in the thickness direction. On the surface of the intermediate plate (63) on the first cylinder (71) side, one end of the communication path (64) is opened at a location on the right side of the first blade (76). On the surface of the intermediate plate (63) on the second cylinder (81) side, the other end of the communication path (64) is opened at a location on the left side of the second blade (86). As shown in FIG. 3 , the communication path (64) extends obliquely with respect to the thickness direction of the intermediate plate (63), and connects the first low pressure chamber (74) and the second high pressure chamber (83). Communicate with each other.

  As described above, the first low pressure chamber (74) of the first rotary mechanism (70) and the second high pressure chamber (83) of the second rotary mechanism (80) are connected via the communication path (64). Communicate with each other. The first low pressure chamber (74), the communication passage (64), and the second high pressure chamber (83) form one closed space, and this closed space constitutes the expansion chamber (66).

  The front head (61) has a shape in which the central portion projects downward. Further, a through hole is formed in the central portion of the front head (61), and the output shaft (32) is inserted through the through hole. The front head (61) constitutes a slide bearing that supports a lower portion of the first eccentric portion (79) of the output shaft (32). In the front head (61), a circumferential groove is formed in a lower portion of the through hole through which the main shaft portion (38) of the output shaft (32) is inserted. The circumferential groove is formed at a position facing the end of the oil supply passage (90) that opens to the outer peripheral surface of the output shaft (32), and constitutes the lower oil sump chamber (102).

  A through hole is formed in the center of the rear head (62), and the main shaft (38) of the output shaft (32) is inserted through the through hole. The rear head (62) constitutes a slide bearing that supports the upper portion of the second eccentric portion (89) in the output shaft (32).

  The upper plate (65) is formed in a slightly thick disk shape and is placed on the rear head (62). In the upper plate (65), a circular recess is formed at the center of the lower surface. The upper plate (65) is provided at a position where the recessed portion faces the upper end surface of the output shaft (32). The upper plate (65) is connected to the end of the oil supply pipe (41). The terminal end of the oil supply pipe (41) passes through the upper plate (65) from the upper side to the lower side and opens into the recessed part. The recessed portion of the upper plate (65) constitutes an upper oil sump chamber (101) for accumulating refrigerating machine oil supplied from the oil supply pipe (41). Further, the upper plate (65) has a concave groove (103) formed on the lower surface thereof. The concave groove (103) extends from the periphery of the upper oil sump chamber (101) toward the outer periphery of the upper plate (65).

  In the expansion mechanism (31), a first oil passage (111) is formed in the rear head (62), a second oil passage (112) is formed in the intermediate plate (63), and a third oil passage is formed in the front head (61). (113) is formed. The first oil passage (111) penetrates the rear head (62) in the thickness direction, and the end of the concave groove (103) communicates with the bush hole (88) of the second cylinder (81). The second oil passage (112) penetrates the intermediate plate (63) in the thickness direction, and communicates the bush hole (88) of the second cylinder (81) with the bush hole (78) of the first cylinder (71). Yes. In the front head (61), one end of the third oil passage (113) opens to a portion of the upper surface of the front head (61) that faces the bush hole (78) of the first cylinder (71). Further, in the front head (61), the other end of the third oil passage (113) opens to the inner peripheral surface of the through hole through which the output shaft (32) is inserted.

  In the expansion mechanism (31) of the present embodiment configured as described above, the first cylinder (71), the bush (77) provided therein, the first piston (75), and the first blade (76) ) Constitutes the first rotary mechanism (70). The second cylinder (81), the bush (87) provided there, the second piston (85), and the second blade (86) constitute a second rotary mechanism (80). .

-Driving action-
The operation of the air conditioner (10) will be described.

<Cooling operation>
During the cooling operation, the first four-way switching valve (12) and the second four-way switching valve (13) are set to the first state (the state indicated by the solid line in FIG. 1), and the refrigerant circulates in the refrigerant circuit (11). A compression refrigeration cycle is performed. In the refrigeration cycle performed in the refrigerant circuit (11), the high pressure is set to a value higher than the critical pressure of carbon dioxide as a refrigerant.

  In the compressor (20), the compression mechanism (21) is rotationally driven by the electric motor (23). The compression mechanism (21) compresses the refrigerant sucked from the suction pipe (25) and discharges it into the compressor casing (24). The high-pressure refrigerant in the compressor casing (24) is discharged from the compressor (20) through the discharge pipe (26). The refrigerant discharged from the compressor (20) is sent to the outdoor heat exchanger (14) to radiate heat to the outdoor air. The high-pressure refrigerant radiated by the outdoor heat exchanger (14) flows into the expander (30).

  In the expander (30), the high-pressure refrigerant that has flowed into the expansion mechanism (31) through the inflow pipe (35) expands, and thereby the generator (33) is rotationally driven. The electric power generated by the generator (33) is supplied to the electric motor (23) of the compressor (20). The refrigerant expanded by the expansion mechanism (31) is sent out from the expander (30) through the outflow pipe (36). The refrigerant sent from the expander (30) is sent to the indoor heat exchanger (15). In the indoor heat exchanger (15), the refrigerant that has flowed in absorbs heat from the room air and evaporates, thereby cooling the room air. The low-pressure refrigerant discharged from the indoor heat exchanger (15) flows into the suction pipe (25) of the compressor (20).

<Heating operation>
During the heating operation, the first four-way switching valve (12) and the second four-way switching valve (13) are set to the second state (the state indicated by the broken line in FIG. 1), and the refrigerant circulates in the refrigerant circuit (11) to generate steam. A compression refrigeration cycle is performed. As in the cooling operation, the refrigeration cycle performed in the refrigerant circuit (11) has a high pressure set to a value higher than the critical pressure of carbon dioxide, which is a refrigerant.

  In the compressor (20), the compression mechanism (21) is rotationally driven by the electric motor (23). The compression mechanism (21) compresses the refrigerant sucked from the suction pipe (25) and discharges it into the compressor casing (24). The high-pressure refrigerant in the compressor casing (24) is discharged from the compressor (20) through the discharge pipe (26). The refrigerant discharged from the compressor (20) is sent to the indoor heat exchanger (15). In the indoor heat exchanger (15), the refrigerant that has flowed in dissipates heat to the room air, and the room air is heated. The high-pressure refrigerant that has radiated heat from the indoor heat exchanger (15) flows into the expander (30).

  In the expander (30), the high-pressure refrigerant that has flowed into the expansion mechanism (31) through the inflow pipe (35) expands, and thereby the generator (33) is rotationally driven. The electric power generated by the generator (33) is supplied to the electric motor (23) of the compressor (20). The refrigerant expanded by the expansion mechanism (31) is sent out from the expander (30) through the outflow pipe (36). The refrigerant sent from the expander (30) is sent to the outdoor heat exchanger (14). In the outdoor heat exchanger (14), the refrigerant that has flowed in absorbs heat from the outdoor air and evaporates. The low-pressure refrigerant discharged from the outdoor heat exchanger (14) flows into the suction pipe (25) of the compressor (20).

<Lubrication operation of compressor and expander>
The operation of lubricating the compressor (20) and the expander (30) with refrigeration oil will be described.

  In the compressor (20), the internal pressure of the compressor casing (24) is substantially the same as the pressure of the refrigerant discharged from the compression mechanism (21). For this reason, the pressure of the refrigerating machine oil accumulated at the bottom of the compressor casing (24) is also substantially the same as the pressure of the refrigerant discharged from the compression mechanism (21). On the other hand, the compression mechanism (21) sucks the low-pressure refrigerant from the suction pipe (25). Therefore, the compression mechanism (21) has a portion that is lower than the internal pressure of the compressor casing (24). For this reason, the refrigeration oil accumulated at the bottom of the compressor casing (24) flows into the compression mechanism (21) through the oil supply passage (90) in the drive shaft (22), and lubricates the compression mechanism (21). Used. The refrigeration oil supplied to the compression mechanism (21) is discharged into the compressor casing (24) together with the compressed refrigerant, and returns to the bottom of the compressor casing (24) again.

  The pressure of the refrigerant circulating in the refrigerant circuit (11) is somewhat reduced from the compressor (20) to the expander (30). For this reason, the pressure of the refrigerant passing through the expansion mechanism (31) is necessarily lower than the internal pressure of the compressor casing (24). For this reason, the refrigeration oil collected at the bottom of the compressor casing (24) flows into the expansion mechanism (31) through the oil supply pipe (41). At that time, the refrigerating machine oil flowing into the oil supply pipe (41) is cooled by exchanging heat with the refrigerant in the suction side pipe (16) in the cooling heat exchanger (46), and then to the expansion mechanism (31). Inflow.

  The refrigerating machine oil that has flowed into the expansion mechanism (31) is used for lubrication of the expansion mechanism (31). Thereafter, a part of this refrigeration oil leaks from the expansion mechanism (31) and accumulates at the bottom of the expander casing (34), and the rest flows out of the expander (30) together with the refrigerant after expansion. The refrigerating machine oil that has flowed out of the expander (30) together with the refrigerant flows through the refrigerant circuit (11) together with the refrigerant, and is sucked into the compressor (20). On the other hand, the refrigerating machine oil accumulated at the bottom of the expander casing (34) flows into the suction side pipe (16) through the oil return pipe (42) and is sucked into the compressor (20) together with the refrigerant. The pressure of the refrigerant flowing through the suction side pipe (16) is the lowest in the refrigerant circuit (11). Therefore, the refrigerating machine oil in the expander casing (34) flows through the oil return pipe (42) and flows into the suction side pipe (16).

  The refrigeration oil sucked together with the refrigerant into the compression mechanism (21) of the compressor (20) is discharged together with the compressed refrigerant from the compression mechanism (21) into the internal space of the compressor casing (24), and then the compressor casing. It flows down to the bottom of (24).

<Operation of expansion mechanism>
The operation of the expansion mechanism (31) will be described with reference to FIG.

  First, a process in which the supercritical high pressure refrigerant flows into the first high pressure chamber (73) of the first rotary mechanism (70) will be described. When the output shaft (32) rotates slightly from the state where the rotation angle is 0 °, the contact position between the first piston (75) and the first cylinder (71) passes through the opening of the inflow port (67), and the inflow port The high-pressure refrigerant starts to flow from (67) into the first high-pressure chamber (73). Thereafter, as the rotation angle of the output shaft (32) gradually increases to 90 °, 180 °, and 270 °, the high-pressure refrigerant flows into the first high-pressure chamber (73). The inflow of the high-pressure refrigerant into the first high-pressure chamber (73) continues until the rotation angle of the output shaft (32) reaches 360 °.

  Next, the process in which the refrigerant expands in the expansion mechanism (31) will be described. When the output shaft (32) rotates slightly from the state where the rotation angle is 0 °, the first low pressure chamber (74) and the second high pressure chamber (83) communicate with each other via the communication path (64), and the first low pressure chamber The refrigerant begins to flow from the chamber (74) into the second high pressure chamber (83). Thereafter, as the rotation angle of the output shaft (32) gradually increases to 90 °, 180 °, and 270 °, the volume of the first low pressure chamber (74) gradually decreases and the volume of the second high pressure chamber (83) gradually increases. As a result, the volume of the expansion chamber (66) gradually increases. This increase in the volume of the expansion chamber (66) continues until just before the rotation angle of the output shaft (32) reaches 360 °. The refrigerant in the expansion chamber (66) expands in the process of increasing the volume of the expansion chamber (66), and the output shaft (32) is rotationally driven by the expansion of the refrigerant. Thus, the refrigerant in the first low pressure chamber (74) flows through the communication passage (64) while expanding into the second high pressure chamber (83).

  Next, the process in which the refrigerant flows out from the second low pressure chamber (84) of the second rotary mechanism (80) will be described. The second low pressure chamber (84) starts to communicate with the outflow port (68) when the rotation angle of the output shaft (32) is 0 °. That is, the refrigerant begins to flow out from the second low pressure chamber (84) to the outflow port (68). Thereafter, the rotation angle of the output shaft (32) gradually increases to 90 °, 180 °, and 270 °, and expands from the second low pressure chamber (84) until the rotation angle reaches 360 °. Later low pressure refrigerant flows out.

  In the expansion mechanism (31), the refrigerating machine oil supplied through the oil supply pipe (41) is introduced into the upper oil sump chamber (101). The refrigerating machine oil that has flowed into the upper oil sump chamber (101) flows into the oil supply passageway (90) of the output shaft (32), the sliding portion of the output shaft (32) and the rear head (62), and the groove (103). Distributed.

  Part of the refrigeration oil that flows into the oil supply passage (90) of the output shaft (32) passes through the branch passages (91, 92) to the sliding part of the eccentric part (79, 89) and the piston (75, 85). Supplied and the remainder flows into the lower oil sump chamber (102). The refrigerating machine oil flowing into the lower oil sump chamber (102) is supplied to the sliding portion between the output shaft (32) and the front head (61).

  The refrigerating machine oil that has flowed into the concave groove (103) flows through the first oil passage (111) into the bush hole (88) of the second cylinder (81). A part of the refrigerating machine oil flowing into the bush hole (88) is a sliding part of the second cylinder (81) and the bush (87) or a sliding part of the second blade (86) and the bush (87). Supplied to. The remainder of the refrigeration oil that has flowed into the bush hole (88) flows into the bush hole (78) of the first cylinder (71) through the second oil passage (112). A part of the refrigerating machine oil flowing into the bush hole (78) is a sliding part between the first cylinder (71) and the bush (77) or a sliding part between the first blade (76) and the bush (77). Supplied to. The remaining refrigerating machine oil flowing into the bush hole (78) is supplied to the gap between the front head (61) and the output shaft (32) through the third oil passage (113).

-Effect of Embodiment 1-
In the present embodiment, the refrigeration oil is stored in the compressor casing (24) whose internal pressure is equal to the pressure of the refrigerant immediately after being discharged from the compression mechanism (21), and the refrigeration oil is stored in the compression mechanism (21) and the expansion mechanism (31 ) To both. That is, in the present embodiment, the refrigerating machine oil is stored in the part having the highest pressure in the refrigerant circuit (11), and the refrigerating machine oil is compressed into a compression mechanism (a part having a lower pressure than the internal pressure of the compressor casing (24)). 21) and expansion mechanism (31). For this reason, the supply source of the refrigerating machine oil is higher than the supply destination, and the refrigerating machine oil is reliably supplied to the compression mechanism (21) and the expansion mechanism (31). Therefore, according to this embodiment, the amount of refrigeration oil supplied to the compression mechanism (21) and the expansion mechanism (31) can be secured, and troubles such as seizure of the compression mechanism (21) and the expansion mechanism (31) can be secured. It is possible to prevent it and ensure the reliability of the air conditioner (10).

  In the present embodiment, the refrigerating machine oil accumulated in the expander casing (34) is returned to the compressor (20) through the oil return pipe (42). Since the amount of refrigerating machine oil present in the refrigerant circuit (11) is constant, if the amount of refrigerating machine oil accumulated in the expander casing (34) increases, the amount of refrigerating machine oil in the compressor casing (24) increases accordingly. The amount of storage will decrease, and there is a possibility that the refrigerating machine oil will not be sufficiently supplied to the compression mechanism (21) and the expansion mechanism (31). On the other hand, in this invention, the refrigerating machine oil in the expander casing (34) is sent back to the compression mechanism (21) through the oil return pipe (42). Therefore, according to this embodiment, a sufficient amount of refrigerating machine oil can be secured in the compressor casing (24), and the refrigerating machine oil can be more reliably supplied to the compression mechanism (21) and the expansion mechanism (31). can do.

  In the present embodiment, the refrigerating machine oil accumulated in the expander casing (34) is sent to the suction side pipe (16). The suction side pipe (16) connected to the suction pipe (25) of the compression mechanism (21) is the lowest pressure part in the refrigerant circuit (11). That is, in the present embodiment, a pressure difference can be reliably generated between the internal space of the expander casing (34) in which the refrigerating machine oil accumulates and the refrigerating machine oil return destination. Therefore, according to the present embodiment, the refrigerating machine oil accumulated in the expander casing (34) can be reliably sent back to the compressor (20), and the amount of refrigerating machine oil stored in the compressor casing (24) is secured. can do.

  Here, in the internal space of the compressor casing (24), the refrigeration oil and the refrigerant discharged from the compression mechanism (21) coexist. For this reason, the temperature of the refrigerating machine oil stored in the compressor casing (24) is approximately the same as the temperature of the refrigerant discharged from the compression mechanism (21). On the other hand, the refrigerant immediately after being discharged from the compression mechanism (21) may reach about 80 ° C to 100 ° C, and is the highest temperature among the refrigerants circulating in the refrigerant circuit (11). For this reason, when the high-temperature refrigeration oil stored in the compressor casing (24) is supplied to the expansion mechanism (31) as it is, the refrigerant of about 0 ° C. to 30 ° C. passing through the expansion mechanism (31) is heated by the refrigeration oil. Then, the enthalpy of the refrigerant flowing out from the expansion mechanism (31) rises. If the enthalpy of the refrigerant flowing out from the expansion mechanism (31) increases, the amount of heat absorbed by the refrigerant in the indoor heat exchanger (15) and outdoor heat exchanger (14) may decrease, leading to a reduction in the capacity of the air conditioner (10). There is.

  On the other hand, in this embodiment, the refrigerating machine oil flowing out of the compressor casing (24) and flowing through the oil supply pipe (41) is cooled by the cooling heat exchanger (46) and then supplied to the expansion mechanism (31). is doing. For this reason, compared with the case where the refrigerating machine oil stored in the compressor casing (24) is directly introduced into the expansion mechanism (31), the refrigerating machine oil supplied through the oil supply pipe (41) passes through the expansion mechanism (31). The amount of heat entering the refrigerant can be reduced. Therefore, according to this embodiment, the enthalpy of the refrigerant flowing out from the expansion mechanism (31) can be suppressed to a low level, and a decrease in the cooling capacity and heating capacity of the air conditioner (10) can be suppressed.

  In particular, in the present embodiment, the refrigerant sucked into the compression mechanism (21) (that is, the coldest refrigerant among the refrigerant circulating in the refrigerant circuit (11)) and the refrigerating machine oil flowing through the oil supply pipe (41) In the cooling heat exchanger (46). Therefore, according to this embodiment, the temperature of the refrigerating machine oil introduced into the expansion mechanism (31) through the oil supply pipe (41) can be reliably reduced, and the capacity reduction of the air conditioner (10) can be more reliably performed. Can be suppressed.

-Modification 1 of Embodiment 1-
In the air conditioner (10) of the present embodiment, as shown in FIG. 5, in addition to the cooling heat exchanger (46) connected to the oil supply pipe (41) and the suction side pipe (16), the oil supply pipe ( 41) and a cooling heat exchanger (47) connected to the oil return pipe (42) may be provided. The cooling heat exchanger (47) exchanges heat between the refrigerating machine oil flowing through the oil supply pipe (41) and the refrigerant flowing through the oil return pipe (42).

  As described above, the temperature of the refrigerant passing through the expansion mechanism (31) is about 0 ° C to 30 ° C. For this reason, the temperature of the refrigerating machine oil that leaks from the expansion mechanism (31) and accumulates in the expander casing (34) is a relatively low value that is comparable to the temperature of the refrigerant passing through the expansion mechanism (31). In the cooling heat exchanger (47), the relatively high temperature refrigerating machine oil flowing out of the compressor casing (24) and flowing through the oil supply pipe (41) flows out of the expander casing (34) and returns to the oil return pipe. Heat exchange with relatively low temperature refrigeration oil flowing through (42).

  Refrigerating machine oil cooled in order by these two cooling heat exchangers (46, 47) is introduced into the expansion mechanism (31). The temperature of the refrigerating machine oil introduced into the expansion mechanism (31) through the oil supply pipe (41) can be further lowered, and it becomes possible to more reliably suppress a reduction in the capacity of the air conditioner (10).

-Modification 2 of Embodiment 1
In the air conditioner (10) of this embodiment, as shown in FIG. 6, in addition to the cooling heat exchanger (46) connected to the oil supply pipe (41) and the suction side pipe (16), the oil supply pipe ( 41) A cooling heat exchanger (48) for exchanging heat between the refrigerating machine oil and outdoor air may be provided. In the oil supply pipe (41), the cooling heat exchanger (48) is arranged upstream of the cooling heat exchanger (46) connected to the oil supply pipe (41) and the suction side pipe (16). .

  As described above, the temperature of the refrigerant immediately after being discharged from the compression mechanism (21) reaches about 80 ° C. to 100 ° C., and the temperature of the refrigerating machine oil stored in the compressor casing (24) is also about the same. . On the other hand, the temperature of outdoor air is usually about 30 ° C. to 40 ° C. even in summer, and hardly exceeds 50 ° C. That is, the refrigerating machine oil flowing through the oil supply pipe (41) is hotter than the outdoor air. For this reason, in the cooling heat exchanger (48), the refrigerating machine oil flowing through the oil supply pipe (41) is cooled by the outdoor air.

  Refrigerating machine oil cooled in order by these two cooling heat exchangers (48, 46) is introduced into the expansion mechanism (31). For this reason, the temperature of the refrigerating machine oil introduced into the expansion mechanism (31) through the oil supply pipe (41) can be further lowered, and the reduction in the capacity of the air conditioner (10) can be more reliably suppressed.

<< Embodiment 2 of the Invention >>
A second embodiment of the present invention will be described. In this embodiment, the expander casing (34) has a function as an accumulator. Here, about the air conditioner (10) of this embodiment, a different point from the said Embodiment 1 is demonstrated.

  As shown in FIG. 7, in the refrigerant circuit (11) of the present embodiment, the suction side pipe (16) is constituted by a first pipe (17) and a second pipe (18).

  One end of the first pipe (17) is connected to the second port of the first four-way switching valve (12). The other end of the first pipe (17) is connected to the expander casing (34) and opens between the expansion mechanism (31) and the generator (33) in the internal space of the expander casing (34). The first pipe (17) is a first pipe that communicates between the indoor heat exchanger (15) and the outdoor heat exchanger (14) operating as an evaporator and the internal space of the expander casing (34). The suction side passage is configured.

One end of the second pipe (18) is connected to the expander casing (34) and opens between the expansion mechanism (31) and the generator (33) in the internal space of the expander casing (34). The other end of the second pipe (18) is connected to the suction pipe (25) of the compressor (20). The second pipe (18) constitutes a second suction side passage for communicating the internal space of the expander casing (34) and the suction side of the compressor (20). In the present embodiment, the oil return pipe (42) is connected to the upstream side of the cooling heat exchanger (46) in the second pipe (18).

  Here, in the indoor heat exchanger (15) and the outdoor heat exchanger (14) that operate as an evaporator, the refrigerant flowing into the evaporator does not completely evaporate, and some of the refrigerant is liquid refrigerant. It may flow out of there. In such a case, if the amount of the liquid refrigerant flowing out from the heat exchanger (14, 15) is large, the liquid refrigerant may be sucked into the compression mechanism (21), and the compression mechanism (21) may be damaged.

  On the other hand, in this embodiment, even if the gas-liquid two-phase refrigerant flows into the internal space of the expander casing (34) from the first pipe (17), the refrigerant is gas in the expander casing (34). The refrigerant is separated into the refrigerant and the liquid refrigerant, and the gas refrigerant is sent to the compression mechanism (21) through the second pipe (18). For this reason, the refrigerant sucked into the compression mechanism (21) is almost only gas refrigerant. That is, according to this embodiment, the expander casing (34) can also function as an accumulator, and damage to the compressor (20) due to liquid back can be prevented without providing an accumulator separately.

-Modification of Embodiment 2-
In the present embodiment, the connection position of the first pipe (17) in the expander casing (34) may be changed.

  As shown in FIG. 8, the first pipe (17) of this modification is connected to the lower part of the expander casing (34), and is located below the generator (33) in the internal space of the expander casing (34). It is open. In this modification, the refrigerant flowing into the internal space of the expander casing (34) through the first pipe (17) passes from the bottom to the top of the gap between the rotor and the stator in the generator (33). Then, it flows into the second pipe (18).

  When the refrigerant passes through the generator (33), the liquid refrigerant in the refrigerant adheres to the generator (33) and flows downward, and the gas refrigerant in the refrigerant mainly becomes the generator (33). To reach the second pipe (18). Therefore, according to this modification, gas refrigerant and liquid refrigerant can be reliably separated in the internal space of the expander casing (34), and damage to the compressor (20) due to liquid back can be prevented more reliably. it can.

  In this modification, since the refrigerant passes through the generator (33), the generator (33) is cooled by the refrigerant. Therefore, according to this modification, the temperature rise of the generator (33) can be suppressed, and the efficiency of the generator (33) can be improved.

<< Embodiment 3 of the Invention >>
Embodiment 3 of the present invention will be described. The air conditioner (10) of the present embodiment is obtained by changing the configuration of the expander (30) in the first embodiment. Here, the difference from the first embodiment will be described for the expander (30) of the present embodiment.

  As shown in FIG. 9, one eccentric part (59) is formed in the upper end part of the output shaft (32). The eccentric portion (59) is formed with a larger diameter than the main shaft portion (38) of the output shaft (32). An oil supply passage (90) is formed in the output shaft (32). The oil supply passage (90) extends along the axis of the output shaft (32). One end of the oil supply passageway (90) opens to the upper end surface of the output shaft (32). The other end of the oil supply passageway (90) is bent at a right angle and extends in the radial direction of the output shaft (32), and on the outer peripheral surface of the output shaft (32) that is slightly lowered from the eccentric portion (59). It is open. In the oil supply passage (90), one branch passage (93) extending in the radial direction of the output shaft (32) is formed. The branch passage (93) opens on the outer peripheral surface of the eccentric portion (59).

  The expansion mechanism (31) is a so-called oscillating piston type rotary fluid machine. The expansion mechanism (31) is provided with one front head (61), one cylinder (51), one piston (55), one rear head (62), and one upper plate (65).

  In the expansion mechanism (31), the front head (61), the cylinder (51), the rear head (62), and the upper plate (65) are stacked in order from the bottom to the top. In this state, the cylinder (51) has its lower end face closed by the front head (61) and its upper end face closed by the rear head (62).

  The output shaft (32) passes through the stacked front head (61), cylinder (51), and rear head (62). Moreover, the eccentric part (59) of the output shaft (32) is located in the cylinder (51).

  As shown in FIG. 10, a piston (55) is provided in the cylinder (51). The piston (55) is formed in an annular shape or a cylindrical shape. The inner diameter of the piston (55) is substantially equal to the outer diameter of the eccentric part (59). The eccentric portion (59) of the output shaft (32) passes through the piston (55).

  The piston (55) has an outer peripheral surface in sliding contact with the inner peripheral surface of the cylinder (51), one end surface in sliding contact with the front head (61), and the other end surface in contact with the rear head (62). A fluid chamber (52) is formed in the cylinder (51) between its inner peripheral surface and the outer peripheral surface of the piston (55).

  A blade (56) is provided integrally with the piston (55). The blade (56) is formed in a plate shape extending in the radial direction of the piston (55), and projects outward from the outer peripheral surface of the piston (55). The blade (56) is inserted into the bush hole (58) of the cylinder (51). The bush hole (58) of the cylinder (51) penetrates the cylinder (51) in the thickness direction, and opens to the inner peripheral surface of the cylinder (51).

  The cylinder (51) is provided with a pair of bushes (57). Each bush (57) is a small piece formed such that the inner surface is a flat surface and the outer surface is a circular arc surface. In the cylinder (51), the pair of bushes (57) are inserted into the bush holes (58) and sandwich the blade (56). The inner surface of the bush (57) is in sliding contact with the blade (56), and the outer surface of the bush (57) slides with the cylinder (51). The blade (56) integral with the piston (55) is supported by the cylinder (51) via the bush (57), and is rotatable and advanceable / retractable with respect to the cylinder (51).

  The fluid chamber (52) in the cylinder (51) is partitioned by a blade (56) integral with the piston (55), and the left side of the blade (56) in FIG. 10 is a high pressure chamber (53) on the high pressure side. The right side is a low pressure side low pressure chamber (54). An inflow port (67) is formed in the front head (61). The inflow port (67) opens to a portion of the upper surface of the front head (61) facing the high pressure chamber (53). The opening position of the inflow port (67) is set in the vicinity of the inner peripheral surface of the cylinder (51) and in the vicinity of the left side of the blade (56) in FIG. An outflow port (68) is formed in the cylinder (51). The outflow port (68) opens at a position slightly on the right side of the bush (57) in FIG. 10 on the inner peripheral surface of the cylinder (51). The outflow port (68) can communicate with the low pressure chamber (54).

  The front head (61) has a shape in which the central portion projects downward. A through hole is formed in the center of the front head (61), and the main shaft (38) of the output shaft (32) is inserted through the through hole. The front head (61) constitutes a sliding bearing that supports a lower portion of the eccentric portion (59) of the output shaft (32). In the front head (61), a circumferential groove is formed below the through hole through which the output shaft (32) is inserted. The circumferential groove is formed at a position facing the end of the oil supply passage (90) that opens to the outer peripheral surface of the output shaft (32), and constitutes the lower oil sump chamber (102). The overall shape of the front head (61) and the point that the lower oil sump chamber (102) is formed in the front head (61) are the same as in the first embodiment.

  A through hole is formed in the center of the rear head (62), and the main shaft (38) of the output shaft (32) is inserted through the through hole. The rear head (62) constitutes a sliding bearing that supports the upper portion of the eccentric portion (59) of the output shaft (32). In addition, a circular recess is formed coaxially with the through hole at the center of the upper surface of the rear head (62). This recess constitutes an upper oil sump chamber (101) for accumulating refrigeration oil supplied from the oil supply pipe (41). Further, a concave groove (103) is formed on the upper surface of the rear head (62). The concave groove (103) extends from the periphery of the upper oil sump chamber (101) toward the outer periphery of the rear head (62).

  The upper plate (65) is formed in a slightly thick disk shape and is placed on the rear head (62). The upper plate (65) is connected to the end of the oil supply pipe (41). The end of the oil supply pipe (41) passes through the upper plate (65) from the upper side to the lower side and opens to the upper oil sump chamber (101).

  In the expansion mechanism (31), a first oil passage (121) is formed in the rear head (62), and a second oil passage (122) is formed in the front head (61). The first oil passage (121) penetrates the rear head (62) in the thickness direction, and the end of the concave groove (103) communicates with the bush hole (58) of the cylinder (51). In the front head (61), one end of the second oil passage (122) opens to a portion of the upper surface of the front head (61) that faces the bush hole (58) of the cylinder (51). Further, in the front head (61), the other end of the second oil passage (122) opens to the inner peripheral surface of the through hole through which the output shaft (32) is inserted.

-Driving action-
The cooling operation and heating operation of the air conditioner (10) and the operation of supplying the refrigeration oil to the compression mechanism (21) and the expansion mechanism (31) are the same as in the case of the first embodiment. Here, the operation of the expansion mechanism (31) of the present embodiment for recovering power from the refrigerant will be described with reference to FIG.

  When the output shaft (32) is slightly rotated counterclockwise from the state (rotation angle is 0 °) in the figure (a), the inflow port (67) communicates with the high pressure chamber (53), High-pressure refrigerant flows from the inflow port (67) into the high-pressure chamber (53). At this time, the low pressure chamber (54) communicates with the outflow port (68), and the pressure of the low pressure chamber (54) is substantially equal to the low pressure of the refrigeration cycle. For this reason, the piston (55) is pushed and moved by the refrigerant flowing into the high pressure chamber (53), and the output shaft (32) continues to rotate counterclockwise in FIG.

  Then, as shown in the figures (b) to (d) in sequence, the volume of the high pressure chamber (53) increases as the piston (55) moves, while the volume of the low pressure chamber (54) increases as the piston (55). As it moves, it shrinks. Thereafter, the piston (55) returns to the state shown in FIG. 5 (a), but continues to rotate due to the inertial force, and the inflow port (67) communicates with the high pressure chamber (53) again and at the same time the outflow port (54) 68) is in communication, and the output shaft (32) is continuously rotated.

  In the expansion mechanism (31), the refrigerating machine oil supplied through the oil supply pipe (41) is introduced into the upper oil sump chamber (101). The refrigerating machine oil that has flowed into the upper oil sump chamber (101) flows into the oil supply passageway (90) of the output shaft (32), the sliding portion of the output shaft (32) and the rear head (62), and the groove (103). Distributed.

  A part of the refrigeration oil that flows into the oil supply passage (90) of the output shaft (32) is supplied to the sliding surfaces of the eccentric part (59) and the piston (55) through the branch passage (93), and the rest is on the lower side. It flows into the oil sump chamber (102). The refrigerating machine oil flowing into the lower oil sump chamber (102) is supplied to the sliding portion between the output shaft (32) and the front head (61).

  The refrigerating machine oil that has flowed into the recessed groove (103) flows into the bush hole (58) of the cylinder (51) through the first oil passage (121). A part of the refrigerating machine oil flowing into the bush hole (58) is supplied to the sliding portion of the cylinder (51) and the bush (57) and the sliding portion of the blade (56) and the bush (57). . The remaining refrigerating machine oil flowing into the bush hole (58) is supplied to the gap between the front head (61) and the output shaft (32) through the second oil passage (122).

-Modification of Embodiment 3-
In the present embodiment, the oil supply pipe (41) may be connected to the front head (61) of the expansion mechanism (31).

  As shown in FIG. 11, in the expansion mechanism (31) of the present modification, the oil supply pipe (41) is connected to the front head (61) from the outside in the radial direction. The oil supply pipe (41) communicates with the second oil passage (122) of the front head (61). In the front head (61) of this modification, a circumferential groove is formed at the upper end portion of the through hole through which the main shaft portion (38) of the output shaft (32) is inserted, and this circumferential groove is formed in the lower oil sump chamber ( 102). In the front head (61), the second oil passage (122) communicates with the lower oil sump chamber (102).

  In the output shaft (32) of this modification, the lower end of the oil supply passage (90) opens near the lower side of the eccentric portion (59) of the outer peripheral surface of the output shaft (32), and the lower oil sump chamber (102 ). The output shaft (32) is formed with another branch passage (94) in addition to the branch passage (93) opened on the outer peripheral surface of the eccentric portion (59). This branch passage (94) is open near the upper side of the eccentric part (59) in the outer peripheral surface of the output shaft (32).

  In the expansion mechanism (31) of this modification, the refrigerating machine oil supplied through the oil supply pipe (41) is introduced into the second oil passage (122). The refrigerating machine oil flowing into the second oil passage (122) is distributed to the lower oil sump chamber (102) and the bush hole (58) of the cylinder (51).

  The refrigerating machine oil that has flowed into the lower oil sump chamber (102) is distributed to the oil supply passageway (90) of the output shaft (32) and the sliding portion of the output shaft (32) and the front head (61). Part of the refrigerating machine oil that has flowed into the oil supply passageway (90) of the output shaft (32) is supplied to the sliding part of the eccentric part (59) and the piston (55) through the branch passageway (93), and the rest A part is supplied to the sliding part of the output shaft (32) and the rear head (62) through the branch passage (94), and the remainder flows into the upper oil sump chamber (101).

  Part of the refrigerating machine oil that has flowed into the bush hole (58) of the cylinder (51) is the sliding part of the cylinder (51) and the bush (57), or the sliding part of the blade (56) and the bush (57). Supplied to. The remaining refrigerating machine oil that has flowed into the bush hole (58) flows into the upper oil sump chamber (101) through the first oil passage (121).

<< Other Embodiments >>
In each of the above embodiments, the expansion mechanism (31) may be configured by a so-called rolling piston type rotary fluid machine. In this case, in the expansion mechanism (31), the blades (56, 76 , 86) are formed separately from the pistons (55, 75, 85). The blades (56, 76 , 86) are supported so as to advance and retreat with respect to the cylinders (51, 71, 81), and their tips are pressed against the outer peripheral surfaces of the pistons (55, 75, 85).

  In each of the above embodiments, the expansion mechanism (31) may be configured by a scroll type fluid machine. In this case, in the expansion mechanism (31), the refrigerant expands in the expansion chamber formed by the fixed scroll and the movable scroll, and the output shaft engaged with the movable scroll is rotationally driven.

  In each of the above embodiments, the air conditioner is configured by the refrigeration apparatus. However, the water heater is configured by the refrigeration apparatus, and water is heated by the refrigerant discharged from the compressor (20) to generate hot water. It may be.

  In the first modification of the first embodiment, the cooling heat exchanger (46) for exchanging heat between the refrigerating machine oil in the oil supply pipe (41) and the refrigerant in the suction side pipe (16) is omitted, and the oil supply pipe ( Only the cooling heat exchanger (47) for exchanging heat between the refrigeration oil of 41) and the refrigeration oil in the oil return pipe (42) may be provided in the air conditioner (10).

  In the second modification of the first embodiment, the cooling heat exchanger (46) for exchanging heat between the refrigerating machine oil in the oil supply pipe (41) and the refrigerant in the suction side pipe (16) is omitted, and the oil supply pipe ( Only the cooling heat exchanger (48) for exchanging heat between the refrigeration oil of 41) and the outdoor air may be provided in the air conditioner (10).

  In addition, the above embodiment is an essentially preferable illustration, Comprising: It does not intend restrict | limiting the range of this invention, its application thing, or its use.

  As described above, the present invention is useful for a refrigeration apparatus including a compressor and an expander formed separately from each other.

It is a refrigerant circuit figure which shows the structure of the air conditioner in Embodiment 1. It is a schematic longitudinal cross-sectional view which shows the principal part of the expander in Embodiment 1. FIG. 3 is an enlarged view of a main part of an expansion mechanism in Embodiment 1. FIG. FIG. 3 is a schematic cross-sectional view illustrating a state of each rotary mechanism portion for every 90 ° rotation angle of an output shaft in the expansion mechanism of the first embodiment. It is a refrigerant circuit diagram which shows the structure of the air conditioner in the modification 1 of Embodiment 1. It is a refrigerant circuit diagram which shows the structure of the air conditioner in the modification 2 of Embodiment 1. It is a refrigerant circuit diagram which shows the structure of the air conditioner in Embodiment 2. It is a refrigerant circuit figure which shows the structure of the air conditioner in the modification of Embodiment 2. It is a schematic longitudinal cross-sectional view which shows the principal part of the expander in Embodiment 3. FIG. 10 is a schematic cross-sectional view showing the state of the expansion mechanism of Embodiment 3 for every 90 ° rotation angle of the output shaft. It is a schematic longitudinal cross-sectional view which shows the principal part of the expander in the modification of Embodiment 3.

10 Air conditioner (refrigeration equipment)
11 Refrigerant circuit
17 first piping (first suction-side passageway)
18 second piping (second suction-side passageway)
20 Compressor
21 Compression mechanism
24 Compressor casing
30 expander
31 Expansion mechanism
33 Generator
34 Expander casing
41 Lubrication piping (oil supply passage)
42 Oil return piping (oil return passage)
46 Heat exchanger for cooling
47 Heat exchanger for cooling
48 Heat exchanger for cooling

Claims (6)

A refrigeration apparatus comprising a refrigerant circuit (11) to which a compressor (20) and an expander (30) are connected, and performing a refrigeration cycle by circulating refrigerant in the refrigerant circuit (11),
The compressor (20) includes an airtight container-like compressor casing (24) to which a suction pipe (25) is attached , and is accommodated in the compressor casing (24) and sucked from the suction pipe (25) . A compression mechanism (21) that compresses the refrigerant and discharges the refrigerant into the compressor casing (24), and supplies the lubricating oil stored in the compressor casing (24) to the compression mechanism (21). Composed of
The expander (30)
An expansion mechanism (31) for generating power by expanding the flowing refrigerant;
An expander casing (34) that houses the expansion mechanism (31) ;
An inflow pipe (35) that penetrates the expander casing (34) and is connected to the expansion mechanism (31) to introduce refrigerant into the expansion mechanism (31);
While having an outflow pipe (36) that penetrates the expander casing (34) and is connected to the expansion mechanism (31) to draw refrigerant from the expansion mechanism (31) ,
An oil return pipe (42) for introducing the lubricating oil accumulated in the expander casing (34) into the suction pipe (25) of the compressor (20) is provided,
One end is connected to the bottom of the compressor casing (24), the other end passes through the expander casing (34) and the other end is connected to the expansion mechanism (31 ), and is stored in the compressor casing (24). An oil supply pipe (41) for supplying the lubricating oil to the expansion mechanism (31 ) is provided,
In the expansion mechanism (31), the inflow pipe (35) communicates with the fluid chamber (72) where the refrigerant expands, and the oil supply pipe (41) communicates with the oil passage (111, 112, 113) through which the lubricating oil flows. ,
The refrigeration apparatus characterized in that the expansion mechanism (31) is lubricated by the lubricating oil supplied through the oil supply pipe (41) . In claim 1 ,
A refrigeration comprising a cooling heat exchanger (46) for cooling the lubricating oil flowing through the oil supply pipe (41) by heat exchange with the refrigerant sucked into the compression mechanism (21). apparatus. In claim 1 ,
A refrigeration comprising a cooling heat exchanger (47) for cooling the lubricating oil flowing through the oil supply pipe (41) by exchanging heat with the lubricating oil flowing through the oil return pipe (42). apparatus. In claim 1,
A refrigeration system comprising a cooling heat exchanger (48) for cooling the lubricating oil flowing through the oil supply pipe (41) by exchanging heat with outdoor air. In any one of Claims 1 thru | or 4 ,
The refrigerant circuit (11) includes a first suction side passage (17) for communicating the evaporator of the refrigerant circuit (11) and the internal space of the expander casing (34), and the expander casing (34). A second suction side passage (18) for communicating the internal space of the compression mechanism (21) with the suction side of the compression mechanism (21),
The expander casing (34) is configured to separate the refrigerant flowing in from the first suction side passage (17) into a gas refrigerant and a liquid refrigerant and send the gas refrigerant to the second suction side passage (18). A refrigeration apparatus characterized by comprising: In claim 5 ,
The expander (30) includes a generator (33) housed in the expander casing (34) and driven by the expansion mechanism (31),
In the internal space of the expander casing (34), the first suction side passage (17) communicates with a lower portion of the generator (33), and the upper portion of the generator (33) 2. A refrigeration apparatus characterized in that the suction side passage (18) is in communication.

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