JP2008175110A - Compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a dead volume produced at the opening end of a bypass passage without increasing cost for manufacturing a valve element. <P>SOLUTION: In this two-stage compressor 20, the bypass passage 66 for discharging a part of a refrigerant in a low stage side cylinder chamber 42a and returning it to the suction side of a low stage side compression mechanism 40a is formed in a rear head 45. The two-stage compressor 20 comprises an opening/closing mechanism having a valve element 46 for opening and closing the upstream end of the bypass passage 66 opening to the low stage side cylinder chamber 42a. The valve element 46 is so formed that its end surface opposed to the low stage side cylinder chamber 42a is flat. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a compressor provided with a compression mechanism in which a part of refrigerant in a compression chamber is discharged through a bypass passage to make the capacity variable.

  2. Description of the Related Art Conventionally, there has been known a compressor that controls a capacity by providing a bypass passage that communicates between a compression chamber and a suction side, and returning a part of the refrigerant in the compression chamber to the suction side through the bypass passage.

For example, in the compressor disclosed in Patent Document 1, a bypass passage is formed through the side wall of the cylinder, and an upstream end thereof opens to the inner peripheral surface of the cylinder. The bypass passage is provided with an opening / closing mechanism having a valve body for opening and closing the bypass passage. When the bypass passage is closed by this opening / closing mechanism, all of the refrigerant sucked into the compression mechanism is compressed and discharged. On the other hand, when the bypass passage is opened by the opening / closing mechanism, a part of the refrigerant sucked into the compression chamber flows out to the bypass passage, and only the remaining refrigerant is compressed and discharged.
JP 59-12264 A

  However, in the compressor disclosed in Patent Document 1, the valve body of the opening / closing mechanism is configured by a flat member, and the bypass passage is opened so that the valve body does not protrude from the inner peripheral surface of the cylinder to the compression chamber side. It is arranged at a position slightly recessed in the cylinder side wall from the end. As a result, a dead volume is generated between the open end of the bypass passage and the valve body.

  On the other hand, in order to eliminate this dead volume, it is conceivable to form and arrange the front end surface of the valve body so as to be flush with the inner peripheral surface of the cylinder. It is necessary to form the same curved shape as the inner peripheral surface of the cylinder, which increases the manufacturing cost of the valve body.

  This invention is made | formed in view of this point, The place made into the objective is to reduce the dead volume which arises in the opening edge part of a bypass channel, without increasing the manufacturing cost of a valve body.

  In the present invention, the bypass passage (66,266) is formed so as to open on the flat surface of the end plate member (45,46,244,246), and the tip surface of the valve body (64,264) that opens and closes the bypass passage (66,266) is flat. It is formed so as to be flat like the surface.

  The first invention has two end plate members (45, 46, 244, 246) each having a flat surface and arranged so that the flat surfaces face each other, and the two end plate members (45, 46, 244, 246). Between the fixing member (41a, 41b) disposed between the two end plate members (45, 46, 244, 246) and the compression member (42a) between the fixing member (41a, 41b). , 42b) and a movable member (47a, 47b) that rotates eccentrically with respect to the fixed member (41a, 41b) and compresses the refrigerant in the compression chamber (42a, 42b) ( Compressors with 40a, 40b) are of interest. In addition, at least one of the two end plate members (45, 46, 244, 246) allows a part of the refrigerant to be discharged from the compression chamber (42a, 42b) to the suction side of the compression mechanism (40a, 40b). An opening / closing mechanism (13, 266) having a valve body (64, 264) for opening and closing the end of the bypass passage (66, 266) that is open to the compression chamber (42a, 42b) is formed. 29, 64, 65, 229, 264, 265), and the valve body (64, 264) has a flat tip surface facing the compression chamber (42a, 42b).

  In the case of the above configuration, the upstream end of the bypass passage (66,266) is opened to the flat surface of the end plate member (45,46,244,246), so that the shape of the tip surface of the valve body (64,264) is flat. Compared with the configuration in which the bypass passage (66,266) that opens to the inner peripheral surface of the cylinder is closed with a valve body (64,264) having a flat tip surface as in the compressor according to Document 1, the upstream end of the bypass passage (66,266) The volume of the space between the valve body (64,264) and the tip surface can be reduced as much as possible. At this time, it is not necessary to form the distal end surface of the valve body (64, 264) as a curved surface, and it is sufficient to form it on a flat surface, so that the manufacturing cost of the valve body (64, 264) can be suppressed.

  According to a second aspect, in the first aspect, the drive shaft has an eccentric shaft portion (35, 36) that is eccentric with respect to the predetermined rotation shaft (X) and is driven to rotate about the rotation shaft (X). The movable member (47a, 47b) is a cylindrical member that is fitted into the eccentric shaft (35, 36), and the bypass passage (66,266) rotates eccentrically. It is assumed that the end plate member (45, 46, 244, 246) is open on the flat surface outside the locus (Z) of the inner peripheral edge of the movable member (47a, 47b).

  As described above, in the configuration in which the end plate member (45, 46, 244, 246) is provided with the bypass passage (66, 266), the high-temperature lubricating oil supplied to the eccentric shaft portion (35, 36) flows into the bypass passage (66, 266). Is a problem. In other words, the eccentric shaft portion (35, 36) into which the movable member (47a, 47b) is fitted reduces the sliding resistance between the movable member (47a, 47b) and the eccentric shaft portion (35, 36). Lubricating oil is supplied for such purposes. Since this lubricating oil is hot and high pressure, if the lubricating oil in the eccentric shaft portion (35, 36) leaks into the bypass passage (66,266) when the movable member (47a, 47b) rotates eccentrically, the bypass passage The gas refrigerant on the suction side connected to the downstream end of (66,266) is heated, causing a reduction in volumetric efficiency.

  Therefore, in the second aspect of the invention, the bypass plate (66,266) is arranged such that the end plate member (45, 266) is located outside the locus (Z) of the inner peripheral edge when the movable member (47a, 47b) rotates eccentrically. 46, 244, 246). In this way, when the movable member (47a, 47b) rotates eccentrically, the inner peripheral edge of the movable member (47a, 47b) straddles the open end of the bypass passage (66, 266). The space on the inner peripheral side of 47b) and the bypass passage (66, 266) are prevented from communicating with each other, and the inflow of lubricating oil into the bypass passage (66, 266) can be prevented.

  According to a third invention, in the first invention, a low-stage compression mechanism (40a, 240a) that compresses refrigerant sucked from outside, and a high-stage that sucks and compresses refrigerant discharged from the low-stage compression mechanism. Side compression mechanism (40b, 240b), and one of the low-stage side and high-stage side compression mechanisms (40a, 240a, 40b, 240b) is configured by the compression mechanism having the bypass passage (66, 266). It shall be.

  In the case of the above configuration, a so-called two-stage compressor is an object. The capacity of the low stage side compression mechanism (40a, 240a, 40b, 240b) is made variable by the bypass passage (66, 266) as described above, so that the low stage side compression mechanism (40a, 240a) ) And the high-stage compression mechanism (40b, 240b) can be made variable.

  According to the present invention, the bypass plate (66,266) is configured to open on the flat surface of the end plate member (45,46,244,246), and the front end surface of the valve body (64,264) that opens and closes the bypass passage (66,266). By flattening, it is possible to reduce the dead volume between the open end of the bypass passage (66,266) and the tip end surface of the valve body (64,264) while suppressing an increase in cost of the valve body (64,264).

  According to the second invention, the bypass passage (66,266) is outside the locus (Z) of the inner peripheral edge of the movable member (47a, 47b) rotating eccentrically on the flat surface of the end plate member (45,46,244,246). The volumetric efficiency is reduced by preventing the lubricating oil supplied to the eccentric shaft part (35, 36) in which the movable member (47a, 47b) is fitted from flowing into the bypass passage (66,266). Can be prevented.

  According to the third aspect of the present invention, the capacity of one of the low-stage and high-stage compression mechanisms (40a, 240a, 40b, 240b) of the two-stage compressor is made variable so that the low-stage compression mechanism ( 40a, 240a) and the high-pressure side compression mechanism (40b, 240b) can also be made variable.

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

Embodiment 1 of the Invention
The air conditioner (10) according to Embodiment 1 of the present invention includes a two-stage compressor (20) as shown in FIG. The air conditioner (10) includes a refrigerant circuit (11).

  The refrigerant circuit (11) includes a two-stage compressor (20), an outdoor heat exchanger (14), an indoor heat exchanger (15), a first expansion valve (16), a second expansion valve (17), four-way A switching valve (12), a three-way switching valve (13), a gas-liquid separator (18), and an accumulator (19) are connected.

  Specifically, the discharge side of the two-stage compressor (20) is connected to the first port of the four-way switching valve (12) via the discharge pipe (23). The suction side of the two-stage compressor (20) is connected to the bottom of the accumulator (19) via the suction pipe (22). The top of the accumulator (19) is connected to the fourth port of the four-way switching valve (12). The outdoor heat exchanger (14) has one end connected to the second port of the four-way selector valve (12) and the other end connected to the bottom of the gas-liquid separator (18) via the second expansion valve (17). Has been. On the other hand, the indoor heat exchanger (15) has one end connected to the third port of the four-way switching valve (12) and the other end connected to the bottom of the gas-liquid separator (18) via the first expansion valve (16). Has been.

  The refrigerant circuit (11) is provided with an injection pipe (24). One end of the injection pipe (24) is connected to the top of the gas-liquid separator (18), and the other end is connected to the two-stage compressor (20). The injection pipe (24) is provided with a solenoid valve (31). When the solenoid valve (31) is opened, the intermediate pressure gas refrigerant in the gas-liquid separator (18) is introduced into the two-stage compressor (20) by the injection pipe (24).

  The refrigerant circuit (11) is provided with a bypass pipe (28) and an introduction pipe (29). The bypass pipe (28) has one end connected to the two-stage compressor (20) and the other end connected to the suction pipe (22). On the other hand, the introduction pipe (29) is provided with a three-way switching valve (13), one end of which is connected to the two-stage compressor (20), and the other end via the three-way switching valve (13). And the suction pipe (22). In the three-way switching valve (13), the introduction pipe (29) communicates between the two-stage compressor (20) and the discharge pipe (23) (indicated by the solid line in FIG. 2), and the introduction pipe (29) has two The stage compressor (20) and the suction pipe (22) are configured to be switched to a state (a state indicated by a broken line in FIG. 2).

  The four-way selector valve (12) is in a state where the first port (P1) and the second port (P2) communicate with each other and the third port (P3) and the fourth port (P4) communicate with each other (indicated by a solid line in FIG. 2). State), the first port (P1) and the third port (P3) communicate with each other, and the second port (P2) and the fourth port (P4) communicate with each other (state indicated by a broken line in FIG. 2). It is comprised so that it may switch to.

  Next, the configuration of the two-stage compressor (20) will be described. As shown in FIG. 1, the two-stage compressor (20) includes a low-stage compression mechanism (40a) and a high-stage compression mechanism (40b) in a casing (21) that is a vertically long and cylindrical sealed container. The compression mechanism (40) and the electric motor (25) are accommodated. In the casing (21), the electric motor (25) is disposed above the compression mechanism (40).

  The casing (21) has a body through which a suction pipe (22), an injection pipe (24), a bypass pipe (28), and an introduction pipe (29) pass. Moreover, the discharge pipe (23) has penetrated the casing (21) in the upper part. The discharge pipe (23) has an inlet side that is bent in the casing (21) and extends in the horizontal direction.

  The electric motor (25) includes a stator (26) and a rotor (27). The stator (26) is fixed to the inner peripheral surface of the casing (21). The rotor (27) is disposed inside the stator (26). A main shaft portion (34) of a shaft (33) extending in the vertical direction is connected to the central portion of the rotor (27).

  The shaft (33) is driven to rotate about a predetermined rotation axis (X) by operating the electric motor (25). A first eccentric shaft portion (35) and a second eccentric shaft portion (36) are formed on the shaft (33) in order from the lower side. The first eccentric shaft portion (35) and the second eccentric shaft portion (36) are formed with a larger diameter than the main shaft portion (34) and eccentric with respect to the rotation axis (X) of the main shaft portion (34). . In the first eccentric shaft portion (35) and the second eccentric shaft portion (36), the eccentric directions with respect to the rotation axis (X) are reversed. Further, the height of the first eccentric shaft portion (35) is higher than that of the second eccentric shaft portion (36). This shaft (33) constitutes a drive shaft member. A low-stage compression mechanism (40a) is connected to the first eccentric shaft portion (35), and a high-stage compression mechanism (40b) is connected to the second eccentric shaft portion (36).

  The bottom part in the casing (21) is configured as an oil reservoir for lubricating oil, and the lower end of the shaft (33) is immersed in the lubricating oil in the oil reservoir. Although not shown, a centrifugal oil pump is provided at the lower end of the shaft (33), and the lubricating oil passes through the oil supply passage (53) in the shaft (33), and the low-stage compression mechanism (40a ) And the sliding portion of the high-stage compression mechanism (40b).

  The low-stage side compression mechanism (40a) and the high-stage side compression mechanism (40b) are arranged vertically in the lower position of the electric motor (25). Specifically, in the lower space of the electric motor (25) in the casing (21), the front head (44), the middle plate (46), and the rear head (45) are arranged at intervals from the upper side. Yes. The low-stage compression mechanism (40a) is between the rear head (45) and the middle plate (46), and the high-stage compression mechanism (40b) is between the middle plate (46) and the front head (44). Is provided.

  A shaft (33) passes through the center of these front head (44), middle plate (46) and rear head (45). The first eccentric shaft portion (35) is positioned between the rear head (45) and the middle plate (46), while the second eccentric shaft portion (36) is formed of the middle plate (46) and the front head. Located between (44). The front head (44), the middle plate (46), and the rear head (45) constitute an end plate member, and the surfaces facing each other are formed as flat surfaces.

  The basic configuration of the low-stage compression mechanism (40a) and the high-stage compression mechanism (40b) is substantially the same, and both are constituted by so-called oscillating piston type rotary compressors.

  As shown in FIGS. 1 and 3, the low-stage compression mechanism (40a) includes the rear head (45), the middle plate (46), the low-stage cylinder (41a), and the low-stage cylinder (41a) A low-stage piston (47a) housed in the blade, a blade (38) provided on the low-stage piston (47a), and a bush (39, 39) that supports the blade (38). Yes. This low stage compression mechanism (40a) constitutes a first compression mechanism.

  The low-stage cylinder (41a) is a substantially cylindrical member, and its upper surface is in contact with the lower surface of the middle plate (46), while its lower surface is in contact with the upper surface of the rear head (45). Both the lower surface of the middle plate (46) and the upper surface of the rear head (45) are formed as flat surfaces. This low-stage cylinder (41a) constitutes a fixing member.

  The low-stage piston (47a) is a substantially cylindrical member, and is housed in the low-stage cylinder (41a) in a state of being rotatably fitted in the first eccentric shaft portion (35). Yes. The lower stage piston (47a) has a part of its outer peripheral surface in contact with a part of the inner peripheral surface of the lower stage cylinder (41a), and its upper surface and lower surface are respectively the middle plate (46). It is in contact with the lower surface and the upper surface of the rear head (45). The middle plate (46), the rear head (45), the low-stage cylinder (41a), and the low-stage piston (47a) define a low-stage cylinder chamber (42a). The low stage side piston (47a) constitutes a movable member, and the low stage side cylinder chamber (42a) constitutes a compression chamber.

  As shown in FIG. 3, the low-stage cylinder (41a) has a cylindrical bush hole (56) extending in the direction of the rotation axis (X). It is provided so as to open to the side cylinder chamber (42a). A pair of swing bushes (39, 39) are rotatably provided in the bush hole (56). The pair of swing bushes (39, 39) has a shape in which a cylinder is divided by a plane passing through its central axis, and the arcuate outer peripheral surface of each swing bush (39) is formed in the bush hole (56). It is in sliding contact with the inner peripheral surface.

The low-stage piston (47a) is integrally formed with a blade (38) extending in the radial direction from the side peripheral surface thereof. The blade (38) is supported while being sandwiched between the pair of swing bushes (39, 39). That is, the low-stage piston (47a) is rotatably supported around the central axis of the bush hole (56) by the blade (38) and the pair of swing bushes (39, 39). The lower stage cylinder chamber (42a) is separated from the low pressure side low pressure chamber (42a-Lp) and the high pressure side by the blade (38). Is divided into a high pressure chamber (42a-Hp).

  The low stage side cylinder (41a) is formed with a low stage side suction passage (48a), and the downstream end of the low stage side suction passage (48a) is low in the vicinity of the swing bush (39, 39). A suction port is formed by opening to the low pressure chamber (42a-Lp) of the stage side cylinder chamber (42a). The suction pipe (22) of the refrigerant circuit (11) is connected to the upstream end of the low-stage suction passage (48a). The suction pipe (22) supplies a low-pressure gas refrigerant to the low-stage compression mechanism (40a).

  The middle plate (46) has an intermediate pressure space (50) formed therein. The middle plate (46) is formed with a low-stage discharge passage (49a), and the upstream end of the low-stage discharge passage (49a) is low in the vicinity of the rocking bush (39, 39). A discharge port is formed by opening into the high pressure chamber (42a-Hp) of the stage side cylinder chamber (42a), and its downstream end communicates with the intermediate pressure space (50). Although not shown, the low-stage discharge passage (49a) is provided with a discharge valve that opens a discharge port when a predetermined discharge pressure is reached. Further, the injection pipe (24) is connected to the middle plate (46) so as to communicate with the intermediate pressure space (50). That is, the intermediate pressure space (50) becomes an intermediate pressure atmosphere due to the intermediate pressure gas refrigerant discharged from the low-stage compression mechanism (40a) and the intermediate pressure gas refrigerant supplied via the injection pipe (24). Yes.

  The low-stage piston (47a) is rotated by eccentric rotation about the rotation axis (X) in a state where a part of the outer peripheral surface is in contact with a part of the inner peripheral surface of the low-stage cylinder (41a). The refrigerant is compressed by changing the volume of the stage side cylinder chamber (42a).

  The high-stage compression mechanism (40b) includes the front head (44) and the middle plate (46), a high-stage cylinder (41b), and a high-stage side accommodated in the high-stage cylinder (41b). A piston (47b), a blade (not shown) provided on the high-stage piston (47b), and a bush (not shown) for supporting the blade are configured. This higher stage compression mechanism (40b) constitutes a second compression mechanism. The high-stage compression mechanism (40b) has basically the same configuration as the low-stage compression mechanism (40a), and the components corresponding to the components of the low-stage compression mechanism (40a) are: The subscript “a” in the reference numerals of the components of the low-stage compression mechanism (40a) is changed to “b”.

  The upper stage cylinder (41b) has an upper surface in contact with the front head (44) and a lower surface in contact with the middle plate (46). The high-stage piston (47b) is rotatably fitted in the second eccentric shaft portion (36), and a part of the outer peripheral surface thereof is a part of the inner peripheral surface of the high-stage cylinder (41b). And is accommodated in the high-stage cylinder (41b) in a state of contact with the portion. A high-stage cylinder chamber (42b) is defined by the front head (44), the middle plate (46), the high-stage cylinder (41b), and the high-stage piston (47b). Although not shown, the high-stage piston (47b) is supported in a state in which the blade provided on the high-stage piston (47b) is sandwiched between swinging bushes in the same manner as the low-stage piston (47a). Has been.

  Further, a high-stage suction passage (48b) is formed in the high-stage cylinder (41b). The downstream end of the high-stage suction passage (48b) opens into a low-pressure chamber (not shown) of the high-stage cylinder chamber (42b) in the vicinity of the swing bush to constitute a suction port. On the other hand, the middle plate (46) is formed with a communication passage (57) that opens into the middle pressure space (50) in the upper part thereof, and the downstream end of the communication passage (57) is connected to the high-stage side. It communicates with the upstream end of the suction passage (48b). That is, the low pressure chamber of the high stage side cylinder chamber (42b) communicates with the medium pressure space (50) of the middle plate (46) via the high stage side suction passage (48b) and the communication passage (57).

  On the other hand, a high-stage discharge passage (49b) is formed in the front head (44). The high-stage discharge passage (49b) has an upstream end opened to a high-pressure chamber (not shown) in the high-stage cylinder chamber (42b) in the vicinity of the swinging bush to form a discharge port, and a downstream end Is open on the upper surface of the front head (44). That is, the refrigerant compressed by the high stage side compression mechanism (40b) is discharged into the casing (21) through the high stage side discharge passage (49b). A muffler (58) that covers the high-stage discharge passage (49b) of the high-stage compression mechanism (40b) is provided at the top of the front head (44).

  The low-stage cylinder (41a) and the high-stage cylinder (41b) have the same inner diameter. Further, the low-stage piston (47a) and the high-stage piston (47b) have the same outer diameter. Furthermore, the heights of the low-stage side cylinder (41a) and the low-stage side piston (47a) are higher than those of the high-stage side cylinder (41b) and the high-stage side piston (47b). Therefore, the maximum volume of the low-stage cylinder chamber (42a) (that is, the sum of the volume of the high-pressure chamber and the volume of the low-pressure chamber or the volume of the cylinder chamber when the closing is completed) is It is larger than the maximum volume of the cylinder chamber (42b).

  Next, the bypass passage provided in the low-stage compression mechanism (40a) and its opening / closing mechanism will be described.

  The rear head (45) has a large-diameter valve body accommodation hole (61) drilled from its lower surface to the vicinity of the upper surface, and from the ceiling surface of the valve body accommodation hole (61) to the upper surface of the rear head (45). A small-diameter bypass hole (62) is perforated so as to open to the center. These valve body accommodation hole (61) and bypass hole (62) are coaxially formed. Moreover, the lower end of the valve body accommodation hole (61) is sealed by the lid member (63).

  A valve body (64) and a spring member (65) for opening and closing the bypass hole (62) are housed in the valve body housing hole (61). As shown in FIG. 4 (a), the valve body (64) has an outer diameter that increases in two steps from the upper side to the lower side, that is, the upper small diameter part (64a) and the medium diameter medium diameter part. (64b) and a cylindrical member having a lower large-diameter portion (64c). The small diameter part (64a), the medium diameter part (64b) and the large diameter part (64c) are coaxially formed. The outer diameter of the small diameter portion (64a) is substantially the same as the inner diameter of the bypass hole (62), while the outer diameter of the large diameter portion (64c) is substantially the same as the inner diameter of the valve body accommodation hole (61). The small-diameter portion (64a) fits in the bypass hole (62) and the large-diameter portion (64c) fits in the valve element housing hole (61) and slides. The large diameter portion (64c) divides the valve body accommodation hole (61) into an upper space (61a) and a lower space (61b).

  Further, the outer diameter of the medium diameter portion (64b) is smaller than the inner diameter of the valve body housing hole (61), and a spring member (65) is provided around the medium diameter portion (64b). . The spring member (65) is provided in the upper space (61a) so that one end is in contact with the upper surface of the large diameter portion (64c) and the other end is in contact with the ceiling surface of the valve body accommodation hole (61). It has been. When the spring member (65) is in the natural length state, the valve body (64) is pushed down to a position where the small diameter portion (64a) is removed from the bypass hole (62).

  The tip surface of the small diameter portion (64a) is flat so that the valve body (64) is parallel to the upper surface of the rear head (45) when the valve body (64) is housed in the valve body housing hole (61). Is formed. The height of the small-diameter portion (64a) is configured to substantially coincide with the depth of the bypass hole (62) or at least not higher than the depth of the bypass hole (62). That is, the small diameter part (64a) of the valve body (64) is inserted into the bypass hole (62) most when the medium diameter part (64b) contacts the ceiling surface of the valve body accommodation hole (61). However, at this time, the tip surface of the small diameter portion (64a) is flush with the top surface of the rear head (45) or slightly depressed from the top surface of the rear head (45), and the tip of the small diameter portion (64a) Does not protrude into the lower cylinder chamber (42a).

  In addition, a bypass pipe (28) is connected to the rear head (45) so as to open to the upper space (61a), and an introduction pipe (29) is connected to open to the lower space (61b). ing. That is, the lower space (61b) in the valve body housing hole (61) has a state in which the high-pressure refrigerant flowing through the discharge pipe (23) is introduced and a state in which the low-pressure refrigerant flowing through the suction pipe (22) is introduced. Is switched by a three-way selector valve (13).

  The bypass hole (62), the upper space (61a) of the valve element housing hole (61), and the bypass pipe (28) constitute a bypass passage (66). Further, the valve body (64), the spring member (65), the introduction pipe (29), and the three-way switching valve (13) constitute an opening / closing mechanism.

  Specifically, when the three-way switching valve (13) is set to the state shown by the solid line in FIG. 2, the high-pressure refrigerant flowing through the discharge pipe (23) is introduced into the lower space (61b) by the introduction pipe (29). Then, the high-pressure refrigerant contracts the spring member (65) and moves the valve body (64) upward. And as shown to Fig.4 (a), the small diameter part (64a) of a valve body (64) is inserted in a bypass hole (62), and this bypass channel (66) will be in a closed state. Further, when the three-way switching valve (13) is set in a state indicated by a broken line in FIG. 2, the low-pressure refrigerant flowing through the suction pipe (22) is introduced into the lower space (61b) by the introduction pipe (29). Then, the spring member (65) extends to move the valve body (64) downward. And as shown in FIG.4 (b), the small diameter part (64a) of a valve body (64) is pulled out from a bypass hole (62), and a bypass channel (66) will be in an open state. When the bypass passage (66) is thus opened, the low-stage cylinder chamber (42a) communicates with the suction pipe (22).

-Driving action-
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 two-stage compressor (20) will be described.

<Cooling operation>
During the cooling operation, the four-way switching valve (12) is switched to the state shown by the solid line in FIG. When the electric motor (25) of the two-stage compressor (20) is energized in this state, the refrigerant circulates in the refrigerant circuit (11) to perform a vapor compression refrigeration cycle.

  The refrigerant compressed by the two-stage compressor (20) is discharged from the discharge pipe (23), passes through the four-way switching valve (12), is sent to the outdoor heat exchanger (14), and radiates heat to the outdoor air. The high-pressure refrigerant radiated by the outdoor heat exchanger (14) is depressurized by the second expansion valve (17) to become an intermediate-pressure refrigerant and flows into the gas-liquid separator (18). The intermediate pressure refrigerant flowing into the gas-liquid separator (18) is separated into an intermediate pressure gas refrigerant and an intermediate pressure liquid refrigerant. Among them, the intermediate-pressure liquid refrigerant flowing out from the bottom of the gas-liquid separator (18) is decompressed by the first expansion valve (16) to become low-pressure liquid refrigerant and flows into 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 that has flowed out of the indoor heat exchanger (15) sequentially passes through the four-way switching valve (12) and the accumulator (19) and is sucked into the two-stage compressor (20). The two-stage compressor (20) compresses the sucked refrigerant again and discharges it.

  In the cooling operation, when the solenoid valve (31) is set in the open state, the intermediate-pressure gas refrigerant in the gas-liquid separator (18) is transferred to the intermediate pressure space of the two-stage compressor (20) by the injection pipe (24). Introduced to (50). The refrigerant introduced into the intermediate pressure space (50) is compressed by the high stage compression mechanism (40b) together with the refrigerant discharged from the low stage compression mechanism (40a). Details of the operation of the two-stage compressor (20) will be described later.

<Heating operation>
During the heating operation, the four-way switching valve (12) is switched to the state indicated by the broken line in FIG. When the electric motor (25) of the two-stage compressor (20) is energized in this state, the refrigerant circulates in the refrigerant circuit (11) to perform a vapor compression refrigeration cycle.

  The refrigerant compressed by the two-stage compressor (20) is discharged from the discharge pipe (23), passes through the four-way switching valve (12), and flows into 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 refrigerant radiated by the indoor heat exchanger (15) is decompressed by the first expansion valve (16), becomes an intermediate pressure refrigerant, and flows into the gas-liquid separator (18). The intermediate pressure refrigerant flowing into the gas-liquid separator is separated into an intermediate pressure gas refrigerant and an intermediate pressure liquid refrigerant. Among them, the intermediate-pressure liquid refrigerant flowing out from the bottom of the gas-liquid separator (18) is decompressed by the second expansion valve (17) to become a low-pressure liquid refrigerant. The low-pressure liquid refrigerant decompressed by the second expansion valve (17) is sent to the outdoor heat exchanger (14) and absorbs heat from the outdoor air and evaporates. The low-pressure refrigerant flowing out of the outdoor heat exchanger (14) sequentially passes through the four-way switching valve (12) and the accumulator (19) and is sucked into the two-stage compressor (20). The two-stage compressor (20) compresses the sucked refrigerant again and discharges it.

  Also in the heating operation, when the solenoid valve (31) is set to the open state, the intermediate-pressure gas refrigerant in the gas-liquid separator (18) is introduced into the intermediate pressure space (50). The refrigerant introduced into the intermediate pressure space (50) is compressed by the high stage compression mechanism (40b) together with the refrigerant discharged from the low stage compression mechanism (40a).

<Operation of two-stage compressor>
The operation of the two-stage compressor (20) will be described with reference to FIG. In the two-stage compressor (20), when the electric motor (25) is energized, the shaft (33) is rotated by the power generated by the electric motor (25), and the first and second parts provided on the shaft (33). Low-stage and high-stage pistons (47a, 47b) slidably circumscribing the eccentric shafts (35, 36) perform eccentric rotation in the low-stage and high-stage cylinders (41a, 41b), respectively. . As a result, the refrigerant is compressed by the low-stage compression mechanism (40a) and the high-stage compression mechanism (40b). The operation of the two-stage compressor (20) will be described below for each of when the bypass passage (66) is closed and when the bypass passage (66) is open. Since the compression operation of the low-stage compression mechanism (40a) and the high-stage compression mechanism (40b) is basically the same, the low-stage compression mechanism (40a) will be mainly described.

  First, the operation of the two-stage compressor (20) when the bypass passage (66) is closed will be described. As described above, when the three-way switching valve (13) is set to the state shown by the solid line in FIG. 2, the bypass passage (66) is closed.

  The eccentric rotation angle of the low-stage piston (47a) is, in plan view, on the straight line extending in the radial direction from the rotational axis (X) of the shaft (33) and the low-stage piston (47a). (Y) is aligned with the axis of the side piston (47a) (that is, the line connecting the rotating shaft (X) and the swing bush (39, 39)) The eccentric rotation angle at the time when the axis (Y) of the low-stage piston (47a) is located above is 0 °.

  The shaft (33) rotates and the eccentric rotation angle of the low-stage piston (47a) rotates slightly from the 0 ° state, and the low-stage piston (47a) and the low-stage cylinder (41a) come into contact with each other. When the position passes through the opening of the low-stage suction passage (48a), a low-pressure chamber (42a-Lp) is formed in the low-stage cylinder chamber (42a), and the low-pressure chamber is formed from the low-stage suction passage (48a). The refrigerant begins to flow into (42a-Lp). As the eccentric rotation angle of the low-stage piston (47a) increases to 90 °, 180 °, and 270 °, the volume of the low-pressure chamber (42a-Lp) increases and the refrigerant flows into the eccentric rotation angle. The refrigerant continues to flow until the temperature reaches 360 °.

  Thereafter, when the eccentric rotation angle of the low-stage piston (47a) is slightly rotated from a state of 360 ° (ie, 0 °), the contact position between the low-stage piston (47a) and the low-stage cylinder (41a) is changed. Passes through the opening of the lower suction passage (48a). In the low-stage compression mechanism (40a), when the contact position passes through the opening of the low-stage suction passage (48a), the refrigerant is completely closed in the low-pressure chamber (42a-Lp). When the shaft (33) further rotates from this state, the low-pressure chamber (42a-Lp) becomes a high-pressure chamber (42a-Lp) and starts to compress the refrigerant. When the refrigerant pressure in the high pressure chamber (42a-Hp) exceeds the refrigerant pressure in the medium pressure space (50), the discharge valve opens and the refrigerant is discharged from the discharge passage (49a) to the medium pressure space (50). Is done. The discharge of the refrigerant continues until the eccentric rotation angle of the shaft (33) reaches 360 °.

  On the other hand, in the high-stage compression mechanism (40b), similarly to the low-stage compression mechanism (40a), the refrigerant flows into the high-stage cylinder chamber (42b) as the high-stage piston (47b) rotates eccentrically. Inhale and compress inhaled refrigerant. When the pressure of the refrigerant in the high-stage cylinder chamber (42b) exceeds the pressure of the refrigerant in the space in the casing (21), the discharge valve is opened, and the refrigerant is discharged from the discharge passage (49b) to the casing (21 ) Is discharged into the space inside. The refrigerant discharged to the space in the casing (21) is discharged from the discharge pipe (23) to the refrigerant circuit (11). Since the first eccentric shaft portion (35) and the second eccentric shaft portion (36) are eccentric to the opposite side across the rotation shaft (X), the low-stage piston (47a) and the high-stage piston ( With 47b), the rotation is always eccentric with the phase shifted by 180 °.

  Next, the operation of the two-stage compressor (20) when the bypass passage (66) is opened will be described. As described above, when the three-way switching valve (13) is set to the state indicated by the broken line in FIG. 2, the bypass passage (66) is opened.

  The shaft (33) rotates and the eccentric rotation angle of the low-stage piston (47a) rotates slightly from the 0 ° state, and the low-stage piston (47a) and the low-stage cylinder (41a) come into contact with each other. When the position passes through the opening of the low-stage suction passage (48a), the low-pressure chamber (42a-Lp) is formed in the low-stage cylinder chamber (42a) as described above, and the low-stage suction passage (48a) The refrigerant begins to flow into the low pressure chamber (42a-Lp).

  Then, the eccentric rotation angle of the low-stage piston (47a) becomes 0 ° again, and further eccentrically rotates from this state, so that the contact position between the low-stage piston (47a) and the low-stage cylinder (41a) is low. When passing through the opening of the side suction passage (48a), the suction of the refrigerant in the low pressure chamber (42a-Lp) is completed at that time, and the low pressure chamber (42a-Lp) becomes the high pressure chamber (42a-Hp) .

  Here, since the bypass passage (66) is in the open state, even if the low-stage piston (47a) rotates further eccentrically, the high-pressure chamber (42a-Hp) does not compress the refrigerant, The refrigerant in 42a-Hp) is discharged from the bypass hole (62) through the bypass passage (66) to the suction pipe (22). The discharge of the refrigerant continues until the low-stage piston (47a) is in a state of closing the bypass hole (62) (eccentric rotation angle 90 °). Then, when the low-stage piston (47a) closes the bypass hole (62), the discharge of the refrigerant is completed, and at the same time, the confinement of the refrigerant in the high-pressure chamber (42a-Hp) is completed. When the shaft (33) further rotates from this state, compression of the refrigerant in the high pressure chamber (42a-Hp) is started, and the pressure of the refrigerant in the high pressure chamber (42a-Hp) is changed to the refrigerant in the intermediate pressure space (50). When the pressure is exceeded, the discharge valve is opened, and the refrigerant is discharged from the discharge passage (49a) to the intermediate pressure space (50). The discharge of the refrigerant continues until the eccentric rotation angle of the low-stage piston (47a) reaches 360 °.

  Since the process from the refrigerant inflow to the compression in the high stage side compression mechanism (40b) is the same as that in the case where the bypass passage (66) is in the closed state, the description thereof is omitted.

  As described above, when the bypass passage (66) is closed, the contact position between the low-stage piston (47a) and the low-stage cylinder (41a) passes through the opening of the low-stage suction passage (48a). In the low-stage compression mechanism (40a), the refrigerant is completely closed, but when the bypass passage (66) is open, the low-stage piston (47a) closes the bypass hole (62). The closing of the refrigerant in the compression mechanism (40a) is completed. Thus, in the two-stage compressor (20), the closed volume of the low-stage compression mechanism (40a) can be changed by opening and closing the bypass passage (66). As a result, the suction volume of the low-stage compression mechanism (40a) (that is, the maximum volume of the low-stage side cylinder chamber (42a)) and the suction volume of the high-stage compression mechanism (40b) (that is, the high-stage cylinder chamber ( The ratio with the maximum volume) of 42b) changes.

  For example, the ratio K (= V2 / V1) of the suction volume V1 of the low-stage compression mechanism (40a) to the suction volume V2 of the high-stage compression mechanism (40b) when the bypass passage (66) is closed is 0.7. A two-stage compressor (20) designed as described above will be described. When the bypass passage (66) is closed when the pressure difference between the suction refrigerant and the discharge refrigerant is relatively large, the two-stage compressor (20) has a low-pressure side compression mechanism ( 40a) and the higher stage compression mechanism (40b) are performed in a well-balanced manner. In the two-stage compressor (20), the bypass passage (66) is opened when the pressure difference is small, thereby reducing the confining volume of the low-stage compression mechanism (40a). As a result, the ratio K increases, and the compression ratio of the refrigerant in each compression mechanism (40a, 40b) is averaged, so that the low-stage compression mechanism (40a) and the high-stage compression mechanism (40b) The balance of the refrigerant compression stroke is adjusted.

  Here, while the low-stage piston (47a) rotates eccentrically, the inner peripheral edge of the low-stage piston (47a), that is, the internal space of the low-stage piston (47a) is indicated by a one-dot chain line in FIG. Draw the indicated trajectory (Z). That is, the region inside the locus (Z) is a region through which the internal space of the low-stage piston (47a) passes when the low-stage piston (47a) rotates eccentrically, while the locus (Z ) Is an area where the internal space of the low-stage piston (47a) does not pass. The bypass hole (62) opens in a portion of the upper surface of the rear head (45) outside the locus (Z). As a result, while the low-stage piston (47a) rotates eccentrically, the internal space of the low-stage piston (47a) and the bypass hole (62) do not overlap. That is, lubricating oil is supplied to the internal space of the low-stage piston (47a) to reduce the sliding resistance between the low-stage piston (47a) and the first eccentric shaft portion (35). When the low-stage piston (47a) rotates eccentrically, the lubricating oil is prevented from leaking from its internal space to the intake pipe (22) via the bypass hole (62). The locus (Z) is centered on the rotation axis (X), and is the amount of eccentricity from the rotation axis (X) of the first eccentric shaft portion (35) and the inner diameter (radius) of the low-stage side piston (47a). A circle with the sum as the radius.

-Effect of Embodiment 1-
In the first embodiment, the bypass hole (62), which is the upstream end of the bypass passage (66), is opened on the upper surface of the rear head (45), which is a flat surface, and the front end surface of the valve body (64) is flat and the rear head. By forming it parallel to the upper surface of (45), the dead volume between the upper surface of the rear head (45) and the front end surface of the valve body (64) when the bypass passage (66) is closed is made as much as possible. Can be reduced. Thereby, in the closed state of the bypass passage (66), almost no refrigerant remains in the low-stage compression mechanism (40a) without being discharged in the low-stage compression mechanism (40a), so that the low-stage compression mechanism (40a) is connected by connecting the bypass passage (66). ) Can be prevented from lowering the compression efficiency of the refrigerant. At this time, the front end surface of the valve body (64) may be formed as a flat surface, and therefore the front end surface of the valve body (64) is formed on a curved surface along the inner peripheral surface of the low-stage cylinder (61a). In comparison with this, the manufacturing cost of the valve body (64) can be suppressed.

  The tip surface of the valve body (64) is preferably flush with the upper surface of the rear head (45) when the bypass passage (66) is closed. By doing so, the dead volume between the upper surface of the rear head (45) and the front end surface of the valve body (64) can be eliminated, and the compression efficiency of the low-stage compression mechanism (40a) can be further improved. .

  The bypass hole (62), which is the upstream end of the bypass passage (66), is located on the outer surface of the upper surface of the rear head (45) outside the locus (Z) of the internal space of the low-stage piston (47a) that rotates eccentrically. Since it is open to the part, high-pressure and high-temperature lubricating oil supplied to the internal space of the low-stage piston (47a) is prevented from flowing into the suction pipe (22) through the bypass hole (62). be able to. As a result, it is possible to prevent the low-pressure gas refrigerant sucked into the low-stage compression mechanism (40a) from being heated by the lubricating oil and reducing the volumetric efficiency.

  Further, by providing the bypass passage (66), the two-stage compressor (20) having a structure in which the rotation speed of the low-stage compression mechanism (40a) and the rotation speed of the high-stage compression mechanism (40b) are always the same. ), The ratio of the suction volume in each compression mechanism (40a, 40b) can be made variable. For this reason, for example, even if the pressure difference between the suction refrigerant and the discharge refrigerant of the two-stage compressor (20) varies, the low-stage compression mechanism (40a) or the high-stage compression mechanism (40b) By adjusting the suction volume, the compression ratio of the refrigerant in each compression mechanism (40a, 40b) can be averaged. When the compression ratio of the refrigerant in each compression mechanism (40a, 40b) is averaged, the difference between the fluctuation ranges of the compression torque required to compress the refrigerant in each compression mechanism (40a, 40b) becomes small. As a result, the fluctuation of the compression torque in each compression mechanism (40a, 40b) is averaged, and the fluctuation width of the compression torque in the entire two-stage compressor (20) is reduced. Therefore, according to the present embodiment, the suction volume ratio between the low-stage compression mechanism (40a) and the high-stage compression mechanism (40b) is adjusted even if the operating state of the two-stage compressor (20) varies. As a result, the vibration of the two-stage compressor (20) can be kept low.

  In the first embodiment, the amount of refrigerant supplied from the low-stage compression mechanism (40a) to the high-stage compression mechanism (40b) by changing the confining volume of the low-stage compression mechanism (40a). The amount of intermediate pressure gas refrigerant introduced from the injection pipe (24) into the high stage compression mechanism (40b) is adjusted.

  Here, in the conventional two-stage compressor, when the pressure difference between the suction refrigerant and the discharge refrigerant is relatively large, the refrigerant compression process is performed by the low-stage compression mechanism (40a) and the high-stage compression mechanism (40b). )) In a well-balanced manner, the low pressure side compression mechanism (40a) performs most of the refrigerant compression stroke under operating conditions where the pressure difference is relatively small, and the medium pressure space (50) The pressure will be relatively high. In some cases, the amount of intermediate pressure refrigerant introduced from the injection pipe (24) into the intermediate pressure space (50) decreases, and a predetermined economizer effect cannot be obtained. That is, the supply amount of the intermediate pressure refrigerant is reduced, and the enthalpy of the suction refrigerant of the high stage compression mechanism (40b) cannot be sufficiently lowered, and the power required for driving the high stage compression mechanism (40b) may not be reduced. was there. Further, the enthalpy at the inlet of the evaporator (the indoor heat exchanger (15) in the cooling operation and the outdoor heat exchanger (14) in the heating operation) may not be sufficiently reduced.

  In the first embodiment, even in such a case, the low-stage compression mechanism (40a) is replaced with the high-stage compression mechanism (40b) by reducing the confining volume of the low-stage compression mechanism (40a). The amount of refrigerant supplied to can be reduced, and a decrease in the amount of intermediate-pressure gas refrigerant introduced into the high-stage compression mechanism (40b) can be suppressed. Therefore, a predetermined economizer effect is exhibited and the operation efficiency of the two-stage compressor (20) is improved. In addition, the cooling efficiency and heating efficiency of the air conditioner (10) are also improved.

  In the first embodiment, the amount of refrigerant circulating in the refrigerant circuit (11) is reduced without reducing the rotational speed of the electric motor (25) by reducing the confining volume of the low-stage compression mechanism (40a). be able to. Conventionally, the rotational speed of the electric motor (25) has been reduced in order to reduce the amount of refrigerant circulating in the refrigerant circuit (11). Therefore, unlike the prior art, the circulation amount of the refrigerant can be reduced while keeping the electric motor (25) at a rotational speed at which high efficiency is obtained.

<< Embodiment 2 of the Invention >>
Next, Embodiment 2 of the present invention will be described. In the two-stage compressor (220) according to the second embodiment, the bypass passage is provided in the high-stage compression mechanism (240b), and the first embodiment is different in that the confining volume of the high-stage compression mechanism (240b) is changed. And different. In addition, the same code | symbol is attached | subjected to the structure similar to Embodiment 1, and description is abbreviate | omitted.

  Specifically, as shown in FIG. 6, the front head (244) is provided with a large-diameter valve body accommodation hole (261) from the upper surface to the vicinity of the lower surface, as in the rear head (45) of the first embodiment. In addition, a small-diameter bypass hole (262) is bored so as to open from the bottom surface of the valve body housing hole (261) to the lower surface of the front head (244). The valve body accommodation hole (261) and the bypass hole (262) are formed coaxially. Moreover, the lower end of the valve body accommodation hole (261) is sealed by the lid member (263).

  A valve body (264) and a spring member (265) for opening and closing the bypass hole (262) are housed in the valve body housing hole (261). The valve body (264) has an outer diameter that increases in two stages from the lower side to the upper side, that is, the lower small diameter portion (264a), the middle middle diameter portion (264b), and the upper large diameter portion ( 264c). The small diameter part (264a), the medium diameter part (264b), and the large diameter part (264c) are coaxially formed. The outer diameter of the small diameter portion (264a) is substantially the same as the inner diameter of the bypass hole (262), while the outer diameter of the large diameter portion (264c) is substantially the same as the inner diameter of the valve element housing hole (261). The small diameter portion (264a) is fitted into the bypass hole (262), and the large diameter portion (264c) is fitted into the valve body accommodating hole (261) to slide. The large diameter portion (264c) divides the valve body accommodation hole (261) into a lower space (261a) and an upper space (261b).

  The medium diameter part (264b) has an outer diameter that is smaller than the inner diameter of the valve element housing hole (261), and a spring member (265) is provided around the medium diameter part (264b). . The spring member (265) is provided in the lower space (261a) so that one end contacts the lower surface of the large-diameter portion (264c) and the other end contacts the bottom surface of the valve body housing hole (261). ing. When the spring member (265) is in a natural length state, the valve body (264) is pushed up to a position where the small diameter portion (264a) is removed from the bypass hole (262).

  The tip surface of the small diameter portion (264a) is flat and parallel to the upper surface of the front head (244) when the valve body (264) is housed in the valve body housing hole (261). Is formed. The height of the small diameter portion (264a) is configured to substantially coincide with the depth of the bypass hole (262), or at least not higher than the depth of the bypass hole (262). That is, the small diameter portion (264a) of the valve body (264) is inserted into the bypass hole (262) most when the medium diameter portion (264b) contacts the bottom surface of the valve body housing hole (261). However, at this time, the tip surface of the small diameter portion (264a) is flush with the lower surface of the front head (244) or slightly depressed from the lower surface of the front head (244), and the small diameter portion (264a) The tip does not protrude into the low-stage cylinder chamber (42a).

  The front head (244) is connected so that the upstream end of the bypass pipe (228) opens into the lower space (261a), and the downstream end of the introduction pipe (229) is connected to the upper space (261b). It is connected to open. That is, the upper space (261b) in the valve body accommodating hole (261) has a state in which the high-pressure refrigerant flowing through the discharge pipe (23) is introduced and a state in which the low-pressure refrigerant flowing through the suction pipe (22) is introduced. Is switched by a three-way selector valve (13). The downstream end of the bypass pipe (228) opens into the intermediate pressure space (50) of the middle plate (246).

  The bypass hole (262), the lower space (261a) of the valve element housing hole (261), and the bypass pipe (228) constitute a bypass passage (266). The valve body (264), the spring member (265), the introduction pipe (229), and the three-way switching valve (13) constitute an opening / closing mechanism.

  In the two-stage compressor (220) of the second embodiment, for example, the low-stage compression mechanism (240a) is closed with respect to the closed volume V2 of the high-stage compression mechanism (240b) when the bypass passage (266) is closed. The ratio K (= V2 / V1) of the volume V1 is designed to be 0.85. When the bypass passage (266) is closed when the pressure difference between the suction refrigerant and the discharge refrigerant is relatively small in the two-stage compressor (220), the refrigerant compression stroke is reduced to the low-stage compression mechanism ( 240a) and the high-stage compression mechanism (240b) are performed in good balance. In the two-stage compressor (220), the bypass passage (266) is opened in the operating condition where the pressure difference is large, thereby reducing the confining volume of the high-stage compression mechanism (240b). As a result, the ratio K is reduced, and the compression ratio of the refrigerant in each compression mechanism (240a, 240b) is averaged, so that the low-stage compression mechanism (240a) and the high-stage compression mechanism (240b) The balance of the refrigerant compression stroke is adjusted. Further, the pressure in the intermediate pressure space (50) is adjusted to a pressure value that can efficiently obtain a predetermined economizer effect.

  Here, while the high-stage piston (47b) rotates eccentrically, the inner peripheral edge of the high-stage piston (47b), that is, the internal space of the high-stage piston (47b) is a low-stage piston shown in FIG. Draw a locus similar to the locus (Z) of the side piston (47a). That is, the area inside the locus is an area through which the internal space of the high-stage piston (47b) passes when the high-stage piston (47b) rotates eccentrically, while the area outside the locus is outside the locus. The region is a region through which the internal space of the high stage piston (47b) does not pass. The bypass hole (262) opens in a portion of the lower surface of the front head (244) outside the locus. As a result, while the high-stage piston (47b) rotates eccentrically, the internal space of the high-stage piston (47b) and the bypass hole (262) do not overlap. That is, the internal space of the high-stage piston (47b) is supplied with lubricating oil to reduce the sliding resistance between the high-stage piston (47b) and the second eccentric shaft portion (36). When the high-stage piston (47b) rotates eccentrically, the lubricating oil is prevented from leaking from the internal space to the intermediate pressure space (50) via the bypass hole (262). By doing so, it is possible to prevent the low-pressure gas refrigerant sucked into the high-stage compression mechanism (40b) from being heated by the lubricating oil and reducing the volumetric efficiency. The locus of the inner peripheral edge of the high-stage piston (47b) is centered on the rotation axis (X), and the amount of eccentricity of the second eccentric shaft portion (36) from the rotation axis (X) and the high-stage piston. It is a circle whose radius is the sum of the inner diameter (radius) of (47b).

<< Other Embodiments >>
The present invention may be configured as follows with respect to the embodiment.

  That is, in Embodiments 1 and 2, a two-stage compressor having a low-stage side compression mechanism and a high-stage side compression mechanism is targeted, but the present invention is not limited to this. For example, the present invention can be applied to a single-stage compressor having one compression mechanism.

  Further, although only one bypass passage is provided for each compression mechanism, the present invention is not limited to this, and a plurality of bypass passages may be provided in one compression mechanism to adjust the confining volume in a plurality of stages. Good.

  Furthermore, although the bypass hole and the valve body have a circular cross section, the present invention is not limited to this, and any shape can be adopted.

  Furthermore, in the first and second embodiments, the bypass hole and the valve body are disposed on the rear head or the front head, but the present invention is not limited to this, and may be disposed on the middle plate.

  In Embodiments 1 and 2, the compression mechanism is a swing piston type rotary compressor, but is not limited thereto. For example, as in the first and second embodiments, a compressor including a cylinder and a piston housed in the cylinder may be a rotary compressor that rotates eccentrically without rotating. In addition, a cylinder having an outer cylinder portion and an inner cylinder portion, in which an annular compression chamber is formed between the outer cylinder portion and the inner cylinder portion, is stored in the compression chamber in an eccentric state with respect to the cylinder. An annular piston that divides the compression chamber into an outer compression chamber and an inner compression chamber. It may be a compressor. That is, the present invention can be applied to a compressor having an arbitrary structure as long as the compressor compresses the refrigerant by rotating the movable member relatively eccentrically with respect to the fixed member.

  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 two-stage compressor including a low-stage compression mechanism and a high-stage compression mechanism.

It is a longitudinal cross-sectional view of the two-stage compressor which concerns on Embodiment 1 of this invention. It is a refrigerant circuit diagram of an air conditioner. It is a cross-sectional view which shows the structure of the low stage side compression mechanism of a two-stage compressor. It is an expansion longitudinal cross-sectional view of a bypass channel. It is a schematic explanatory drawing which shows operation | movement of a low stage side compressor mechanism. 4 is a longitudinal sectional view of a two-stage compressor according to Embodiment 2. FIG.

Explanation of symbols

X rotation axis
13 Three-way selector valve (open / close mechanism)
29,229 Introduction pipe (opening / closing mechanism)
33 Shaft (drive shaft member)
35 First eccentric shaft (eccentric shaft)
36 Second eccentric shaft (eccentric shaft)
40a Low stage compression mechanism (compression mechanism)
40b High-stage compression mechanism (compression mechanism)
41a Low-stage cylinder (fixing member)
41b High-stage cylinder (fixing member)
42a Low stage cylinder chamber (compression chamber)
42b Higher cylinder chamber (compression chamber)
44 Front head (end plate member)
45 Rear head (end plate member)
46 Middle plate (end plate member)
47a Low stage piston (movable member)
47b High piston (movable member)
64,264 Valve body (opening / closing mechanism)
65,265 Spring member (opening / closing mechanism)
66,266 Bypass passage

Claims (3)

The two end plate members (45, 46, 244, 246) each having a flat surface and disposed so that the flat surfaces face each other are disposed between the two end plate members (45, 46, 244, 246). A compression chamber (42a, 42b) is formed between the fixed member (41a, 41b) and the two end plate members (45, 46, 244, 246) and the fixed member (41a, 41b). And a compression mechanism (40a, 40b) for compressing the refrigerant in the compression chamber (42a, 42b) having a movable member (47a, 47b) that rotates eccentrically with respect to the fixed member (41a, 41b). A compressor,
At least one of the two end plate members (45, 46, 244, 246) discharges a part of the refrigerant from the compression chamber (42a, 42b) and returns it to the suction side of the compression mechanism (40a, 40b). Bypass passage (66,266) is formed for
An opening / closing mechanism (13, 29, 64, 65, 229, 264, 265) having a valve body (64, 264) for opening and closing the end of the bypass passage (66, 266) that opens to the compression chamber (42a, 42b);
The valve body (64, 264) has a flat tip end surface facing the compression chamber (42a, 42b). In claim 1,
A drive shaft member (33) having an eccentric shaft portion (35, 36) eccentric with respect to a predetermined rotation shaft (X) and being driven to rotate about the rotation shaft (X);
The movable member (47a, 47b) is configured by a cylindrical member fitted into the eccentric shaft portion (35, 36),
The bypass passage (66,266) opens on the flat surface of the end plate member (45,46,244,246) outside the locus (Z) of the inner peripheral edge of the movable member (47a, 47b) rotating eccentrically. Compressor characterized by. In claim 1,
A low-stage compression mechanism (40a, 240a) for compressing refrigerant sucked from the outside,
A high-stage compression mechanism (40b, 240b) that sucks and compresses the refrigerant discharged by the low-stage compression mechanism;
One of the low stage side and high stage side compression mechanisms (40a, 240a, 40b, 240b) is constituted by the compression mechanism provided with the bypass passage (66, 266).

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