Rotary compressors and refrigeration systems

Abstract

To improve reliability when the diameter of a drive shaft of a rotary compressor is reduced.SOLUTION: In a rotary compressor (10), a first cylinder chamber (37) defined by a front head (31) and a middle plate (38) is formed inside a first cylinder (35), and a second cylinder chamber (42) defined by the middle plate and a rear head (43) is formed inside a second cylinder (40). The first piston (50) and the second piston (60) are housed in the first cylinder chamber and the second cylinder chamber, respectively. A diameter Ds of both the first cylinder chamber and the second cylinder chamber and a thickness Tm of the middle plate satisfy a relational expression represented by 1 / 30 ≤ Tm / Ds ≤ 1 / 10.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a rotary compressor and a refrigeration device.

Background Art

[0002] As a rotary compressor, a two-cylinder rotary compressor is known. The two-cylinder rotary compressor houses an inner-rotor type motor, a drive shaft connected to the motor, and a compression mechanism driven by the rotation of the drive shaft inside a cylindrical sealed container, and is configured such that the axial direction along the axis of the drive shaft is the vertical direction. The compression mechanism is of a two-cylinder type and includes a first head, a first cylinder, a middle plate, a second cylinder, and a second head.

[0003] The first cylinder forms a first cylinder chamber, and the second cylinder forms a second cylinder chamber. The first head is provided on the upper surface of the first cylinder and partitions the first cylinder chamber. The middle plate is interposed between the first cylinder and the second cylinder to partition the first cylinder chamber and the second cylinder chamber. The second head is provided on the lower surface of the second cylinder and partitions the second cylinder chamber.

[0004] A first roller is housed in the first cylinder chamber, and a second roller is housed in the second cylinder chamber. The crankshaft has a first eccentric portion fitted to the first roller and a second eccentric portion fitted to the second roller, and is supported by the first head and the second head. In the compression mechanism, as the crankshaft rotates, the first roller is eccentrically rotated in the first cylinder chamber and the second roller is eccentrically rotated in the second cylinder chamber. Thereby, fluid is sucked into and compressed in the first cylinder chamber and the second cylinder chamber.

[0005] An example of such a two-cylinder rotary compressor is disclosed in Patent Document 1.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Japanese Patent Publication No. 2014-196714 [Overview of the project] [Problems that the invention aims to solve]

[0007] In rotary compressors like the one described above, there is a desire to reduce the diameter of the drive shaft to increase compression efficiency and improve reliability by reducing the distance between the first and second heads, which are the support points of the drive shaft, thereby suppressing the deflection of the drive shaft. One possible solution is to make the middle plate thinner. However, if the middle plate is made too thin, its strength will decrease, and there is a risk that the middle plate will bend and deform due to the pressure of the fluid compressed in the first and second cylinder chambers. If this happens, the middle plate may come into contact with the first or second roller, compromising the reliability of the rotary compressor.

[0008] The purpose of this disclosure is to improve the reliability when the drive shaft of a rotary compressor is made smaller in diameter. [Means for solving the problem]

[0009] A first aspect of this disclosure relates to a rotary compressor (10). The rotary compressor (10) of the first aspect includes a compression mechanism (30) having a structure in which a first head (31), a first cylinder (35), a middle plate (38), a second cylinder (40), and a second head (43) are stacked, and a drive shaft (25) provided so as to penetrate the compression mechanism (30) in the stacking direction and rotatably supported by the first head (31) and the second head (43). Inside the first cylinder (35) is a first cylinder chamber (37) defined by the first head (31) and the middle plate (38). The first cylinder chamber (37) houses a first piston (50) that compresses the fluid drawn into the first cylinder chamber (37) by eccentric rotation in conjunction with the rotation of the drive shaft (25). A second cylinder chamber (42) is formed inside the second cylinder (40), defined by the middle plate (38) and the second head (43). A second piston (60) is housed in the second cylinder chamber (42) which compresses the fluid drawn into the second cylinder chamber (42) by eccentric rotation in conjunction with the rotation of the drive shaft (25). The diameters Ds of both the first cylinder chamber (37) and the second cylinder chamber (42), or the smaller of the two diameters Ds, and the thickness Tm of the middle plate (38) satisfy the relationship expressed as 1 / 30 ≤ Tm / Ds ≤ 1 / 10.

[0010] In this first embodiment, the thickness Tm of the middle plate (38) is 1 / 30 to 1 / 10 of the diameter Ds of both the first cylinder chamber (37) and the second cylinder chamber (42), or the smaller of the two diameters Ds. When the thickness Tm of the middle plate (38) is 1 / 30 or more of the diameter Ds of a predetermined cylinder chamber (first cylinder chamber (37) or second cylinder chamber (42)), deflection of the middle plate (38) due to the pressure of the fluid compressed in the cylinder chamber can be suitably suppressed. Furthermore, when the thickness Tm of the middle plate (38) is 1 / 10 or less of the diameter Ds of the cylinder chamber, the distance between the first head (31) and the second head (43) can be reduced. This suppresses deflection of the drive shaft (25). Therefore, the reliability of the drive shaft (25) of the rotary compressor (10) can be improved when its diameter is reduced.

[0011] A second aspect of the present disclosure is a rotary compressor (10) of the first aspect, further comprising a casing (11) housing the compression mechanism (30) and the drive shaft (25), a first suction pipe (15) for drawing fluid into the first cylinder chamber (37), and a second suction pipe (16) for drawing fluid into the second cylinder chamber (42). The first suction pipe (15) and the second suction pipe (16) each penetrate the casing (11). Furthermore, the distance L1 between the center (C1) of the portion of the first intake pipe (15) that penetrates the casing (11) and the center (C2) of the portion of the second intake pipe (16) that penetrates the casing (11), and the distance L2 between the center (C3) of the first cylinder chamber (37) in the height direction and the center (C4) of the second cylinder chamber (42) in the height direction, satisfy the relationship expressed as L1 > L2.

[0012] In this second embodiment, the distance L1 between the two centers (C1, C2) of the portions of the first intake pipe (15) and the second intake pipe (16) that penetrate the casing (11) is greater than the distance L2 between the two centers (C3, C4) in the height direction of the first cylinder chamber (37) and the second cylinder chamber (42). This ensures the strength between the portions of the casing (11) through which the first intake pipe (15) and the second intake pipe (16) penetrate.

[0013] A third aspect of the present disclosure is a rotary compressor (10) of the first or second aspect, wherein the first piston (50) and the second piston (60) are eccentric with respect to the axis (AC) of the drive shaft (25). The eccentricity distance Le of the first piston (50) or the second piston (60) with respect to the diameter Ds that satisfies the relational expression of the first aspect, the radius Rs of the first cylinder chamber (37) formed inside the first piston (50), or the radius Rs of the second cylinder chamber (42) formed inside the second piston (60) satisfy the relational expression Le / Rs ≤ 0.25.

[0014] In this third embodiment, the ratio (Le / Rs) of the eccentricity distance Le of the first piston (50) to the radius Rs of the first cylinder chamber (37), or the ratio (Le / Rs) of the eccentricity distance Le of the second piston (60) to the radius Rs of the second cylinder chamber (42), with respect to the diameter Ds satisfying the relational equation of the first embodiment, is 0.25 or less. This allows the amount of deflection of the middle plate (38) to be suitably suppressed and made minute relative to the thickness of the middle plate (38), based on the calculation formula for deflection and stress of the perforated disc. This is advantageous for improving the reliability of the rotary compressor (10).

[0015] A fourth aspect of the present disclosure is a rotary compressor (10) of any one of the first to third aspects, wherein the first suction pipe (15) is connected to the first head (31), or the second suction pipe (16) is connected to the second head (43).

[0016] In this fourth embodiment, the first suction tube (15) is connected to the first head (31), or the second suction tube (16) is connected to the second head (43). This makes it easy to realize a configuration in which the distance between the two centers (C1, C2) of the portions of the first suction tube (15) and the second suction tube (16) that penetrate the casing (11) is greater than the distance between the two centers (C1, C2) of the first cylinder chamber (37) and the second cylinder chamber (42) in the height direction.

[0017] A fifth aspect of the present disclosure is a rotary compressor (10) of any one of the first to third aspects, wherein the first suction pipe (15) is connected to the first head (31) and the second suction pipe (16) is connected to the second cylinder (40), or the first suction pipe (15) is connected to the first cylinder (35) and the second suction pipe (16) is connected to the second head (43).

[0018] In this fifth embodiment, the first suction tube (15) is connected to the first head (31) and the second suction tube (16) is connected to the second cylinder (40), or the first suction tube (15) is connected to the first cylinder (35) and the second suction tube (16) is connected to the second head (43). This configuration specifically makes it possible to realize a configuration in which the distance between the two centers (C1, C2) of the portions of the first suction tube (15) and the second suction tube (16) that penetrate the casing (11) is greater than the distance between the two centers (C3, C4) in the height direction of the first cylinder chamber (37) and the second cylinder chamber (42). Furthermore, since the first suction pipe (15) is connected to the first cylinder (35) or the second suction pipe (16) is connected to the second cylinder (40), the fluid flow path from the first suction pipe (15) to the first cylinder chamber (37) or the second cylinder chamber (42) is shortened compared to the case where the first suction pipe (15) is connected to the first header (31) and the second suction pipe (16) is connected to the second header (43), thereby reducing fluid pressure loss.

[0019] A sixth aspect of the present disclosure is a rotary compressor (10) according to any one of the first to fifth aspects, further comprising an electric motor (21) connected to the drive shaft (25). The electric motor (21) is disposed at a position via the first head (31) between the first cylinder (35). The drive shaft (25) has a main shaft portion (26) supported by the first head (31). The diameter Da of the main shaft portion (26) and the diameter Ds satisfying the relational expression of the first aspect satisfy the relational expression represented by Da ≤ Ds × 0.35.

[0020] In this sixth aspect, the diameter Da of the main shaft portion (26) supported by the first head (31) of the drive shaft (25) is 0.35 times or less the diameter Ds of the first cylinder chamber (37) or the second cylinder chamber (42) satisfying the relational expression of the first aspect. When the diameter Da of the main shaft portion (26) is relatively small in this way, the frictional loss between the main shaft portion (26) and the first head (31) can be reduced. Thereby, the compression efficiency of the rotary compressor (10) can be increased. On the other hand, the drive shaft (25) having a relatively small-diameter main shaft portion (26) is likely to bend during operation of the rotary compressor (10). In the rotary compressor (10) provided with such a drive shaft (25), the technique of the present disclosure can suppress the bending of the drive shaft (25), and thus is particularly effective.

[0021] A seventh aspect of the present disclosure is a rotary compressor (10) according to any one of the first to sixth aspects, further comprising an electric motor (21) connected to the drive shaft (25). The electric motor (21) is disposed at a position via the first head (31) between the first cylinder (35). The drive shaft (25) has a main shaft portion (26) supported by the first head (31) and a sub-shaft portion (29) supported by the second head (43). The diameter Db of the sub-shaft portion (29) and the diameter Da of the main shaft portion (26) satisfy the relational expression represented by Db < Da.

[0022] In this seventh aspect, the diameter Db of the auxiliary shaft portion (29) of the drive shaft (25) supported by the second head (43) is smaller than the diameter Da of the main shaft portion (26) supported by the first head (31). When the diameter Db of the auxiliary shaft portion (29) is smaller than the diameter Da of the main shaft portion (26), the frictional loss between the auxiliary shaft portion (29) and the second head (43) can be reduced as compared with the case where the diameter Db of the auxiliary shaft portion (29) is the same as the diameter Da of the main shaft portion (26). This is advantageous for increasing the compression efficiency of the rotary compressor (10).

[0023] An eighth aspect of the present disclosure is a rotary compressor (10) according to any one of the first to seventh aspects, wherein bearing holes (33, 45) through which the drive shaft (25) is inserted are formed in the first head (31) and the second head (43). Annular grooves (34, 46) extending along the periphery of the bearing holes (33, 45) are formed on the end faces of the first head (31) or the second head (43) on the side of the middle plate (38).

[0024] In this eighth aspect, annular grooves (34, 46) are formed on the end faces of the first head (31) or the second head (43) on the side of the middle plate (38). According to this, an elastically deformable bearing portion (32, 44) can be formed between the annular grooves (34, 46) and the through holes (72) in the first head (31) or the second head (43). During the operation of the rotary compressor (10), the pressure of the fluid compressed in the first cylinder chamber (37) acts on the first piston (50), and the pressure of the fluid compressed in the second cylinder chamber (42) acts on the second piston (60). The compression load thereby applied to the drive shaft (25) causes the drive shaft (25) to deflect in the radial direction. The bearing portions (32, 44) elastically deform toward the annular grooves (34, 46) in accordance with the deflection of the drive shaft (25) when the drive shaft (25) deflects, and deflect together with the drive shaft (25). Thereby, it is possible to avoid the drive shaft (25) from strongly hitting against the bearing portions (32, 44) of the first head (31) or the second head (43), and reduce the wear between the drive shaft (25) and the bearing portions (32, 44).

[0025] A ninth aspect of the present disclosure is a rotary compressor (10) according to any one of the first to eighth aspects, wherein the maximum rotational speed of the drive shaft (25) is 120 rps or more.

[0026] In this ninth embodiment, the maximum rotational speed of the drive shaft (25) is 120 rps or higher, which is relatively high. The faster the rotation of the drive shaft (25) becomes, the greater the deflection of the drive shaft (25) tends to be. In a rotary compressor (10) operated at such a relatively high rotational speed, the technology of this disclosure is particularly effective because it can suppress the deflection of the drive shaft (25).

[0027] A tenth aspect of this disclosure relates to a refrigeration system (1). The refrigeration system (1) of the tenth aspect comprises one rotary compressor (10) of any one of the first to ninth aspects.

[0028] In this tenth aspect, the rotary compressor (10) according to the technology of the present disclosure is provided. In the rotary compressor (10), the reliability is improved when the diameter of the drive shaft (25) of the rotary compressor (10) is reduced. By providing the rotary compressor (10), the energy efficiency can be improved while maintaining the reliability of the refrigeration device (1) by increasing the compression efficiency through the reduction in the diameter of the drive shaft (25). [Brief explanation of the drawing]

[0029] [Figure 1] Figure 1 is a refrigerant circuit diagram illustrating the configuration of a refrigeration system according to an embodiment. [Figure 2] Figure 2 is a longitudinal cross-sectional view illustrating the configuration of a rotary compressor. [Figure 3] Figure 3 is a longitudinal cross-sectional view illustrating the main components of a rotary compressor. [Figure 4] Figure 4 is a cross-sectional view illustrating the configuration of the first cylinder and the first piston. [Figure 5] Figure 5 is a cross-sectional view illustrating the configuration of the second cylinder and the second piston. [Figure 6]Figure 6 is a schematic diagram illustrating a simplified model of the configuration of the first cylinder chamber and the first piston, and the configuration of the second cylinder chamber and the second piston. [Figure 7] Figure 7 is a schematic diagram showing a structural model for the calculation formulas related to the deflection and stress of a perforated disc. [Figure 8] Figure 8 is a graph showing the relationship between the ratio of the diameter of the first or second cylinder chamber to the thickness of the middle plate (Ds / Tm) and an index value indicating the amount of deflection of the middle plate (ymax / t). [Figure 9] Figure 9 is a graph illustrating the relationship between the ratio of the diameter of the first or second cylinder chamber to the thickness of the middle plate (Ds / Tm) and the amount of deflection of the middle plate. [Figure 10] Figure 10 is a longitudinal cross-sectional view illustrating the main parts of a rotary compressor according to the first modified example. [Figure 11] Figure 11 is a longitudinal cross-sectional view illustrating the main parts of a rotary compressor of a second modified example. [Figure 12] Figure 12 is a longitudinal cross-sectional view illustrating the main parts of a rotary compressor according to a third modified example. [Figure 13] Figure 13 is a cross-sectional view illustrating the configuration of the first cylinder and first piston in another embodiment. [Modes for carrying out the invention]

[0030] The following exemplary embodiments will be described in detail with reference to the drawings. The following embodiments will be examples of the application of the rotary compressor according to the present disclosure to a refrigeration system. The drawings are intended to conceptually illustrate the technology of the present disclosure. Therefore, in order to facilitate understanding of the technology of the present disclosure, dimensions, ratios, or numbers may be exaggerated or simplified in the drawings.

[0031] In the following embodiments, the direction along the axis of the drive shaft of the rotary compressor is referred to as the "axial direction," the direction perpendicular to the axial direction is referred to as the "radial direction," and the direction along the circumference of the drive shaft is referred to as the "circumferential direction." Furthermore, the designations "first," "second," etc., are used to distinguish between the phrases to which these designations are attached, and do not limit the number of such phrases or any particular order.

[0032] 《Embodiment》 As shown in Figure 1, the rotary compressor (10) in this embodiment is installed in the refrigeration unit (1).

[0033] -Refrigeration equipment- The refrigeration system (1) includes a refrigerant circuit (1a). The refrigerant circuit (1a) is filled with refrigerant. The refrigerant is an example of a fluid compressed by a rotary compressor (10). The refrigerant circuit (1a) includes a rotary compressor (10), a heat sink (3), a pressure reducing mechanism (4), and an evaporator (5). The pressure reducing mechanism (4) is, for example, an expansion valve. The refrigerant circuit (1a) performs a vapor compression type refrigeration cycle.

[0034] In the refrigeration cycle, a rotary compressor (10) draws in low-pressure gaseous refrigerant, compresses it, and discharges it as high-pressure gaseous refrigerant. The high-pressure gaseous refrigerant compressed by the rotary compressor (10) releases heat into the air in the heat exchanger (3). At this time, the refrigerant liquefies and changes into liquid refrigerant. The liquid refrigerant that has released heat is depressurized by the depressurization mechanism (4). The depressurized liquid refrigerant evaporates in the evaporator (5). At this time, the refrigerant vaporizes and changes into low-pressure gaseous refrigerant. The low-pressure gaseous refrigerant produced in the evaporator (5) is drawn into the rotary compressor (10).

[0035] The refrigeration unit (1) is an air conditioning unit. The air conditioning unit may be a combined cooling and heating unit that switches between cooling and heating. In this case, the air conditioning unit has a switching mechanism that switches the direction of refrigerant circulation. The switching mechanism is, for example, a four-way switching valve. The air conditioning unit may be a cooling-only unit or a heating-only unit. The refrigeration unit (1) may also be a water heater, chiller unit, or cooling unit that cools the air inside a storage area. The cooling unit is a device that cools the air inside a water heater, refrigerator, freezer, container, etc.

[0036] -Rotary Compressor- As shown in Figure 2, the rotary compressor (10) is a two-cylinder rotary compressor. The maximum rotational speed of the rotary compressor (10) is 120 rps or more. Here, "maximum rotational speed" refers to the rotational speed of the drive shaft (25) due to the operation of the electric motor (21), and means the highest rotational speed that can occur within the operating range of the product. Increasing the maximum rotational speed of the rotary compressor (10) is preferable in order to increase the amount of refrigerant circulating in the refrigerant circuit (1a) and to ensure the maximum amount of refrigerant circulating.

[0037] The rotary compressor (10) comprises a casing (11), a drive mechanism (20), and a compression mechanism (30). The drive mechanism (20) and the compression mechanism (30) are housed inside the casing (11).

[0038] <Casing> The casing (11) is composed of a vertically elongated cylindrical sealed container with both ends closed. The casing (11) is installed in an upright position. The casing (11) has a body (12), a lower end plate (13), and an upper end plate (14). The body (12) is formed in a cylindrical shape that extends vertically. The lower end plate (13) is fixed to the lower end of the body (12) and closes its lower end opening. The upper end plate (14) is fixed to the upper end of the body (12) and closes its upper end opening.

[0039] A first suction pipe (15) and a second suction pipe (16) are fixed to the body (12). The first suction pipe (15) and the second suction pipe (16) each pass through the body (12) and are connected to the compression mechanism (30). In this embodiment, the first suction pipe (15) is connected to the first cylinder (35), and the second suction pipe (16) is connected to the rear head (43). A discharge pipe (17) is fixed to the upper end plate (14). The discharge pipe (17) passes through the upper end plate (14) and opens into the upper space inside the casing (11).

[0040] An oil reservoir (18) is provided at the bottom of the casing (11). The oil reservoir (18) is formed by the lower part of the body (12) and the inner walls of the lower end plate (13). Oil is stored in the oil reservoir (18). This oil is used to lubricate the sliding parts of the compression mechanism (30) and the drive shaft (25).

[0041] <Drive mechanism> The drive mechanism (20) includes an electric motor (21) and a drive shaft (25). The electric motor (21) is positioned above the compression mechanism (30). The electric motor (21) is positioned between the first cylinder (35) and the front head (31). The electric motor (21) includes a stator (22) and a rotor (23). The stator (22) and rotor (23) are each formed in a cylindrical shape. The stator (22) is fixed to the inner circumferential surface of the body (12) of the casing (11). The rotor (23) is positioned in the hollow part of the stator (22).

[0042] The drive shaft (25) is inserted through the hollow portion of the rotor (23). The rotor (23) is fixed to the drive shaft (25). When the electric motor (21) is energized, the drive shaft (25) rotates together with the rotor (23). The drive shaft (25) is the shaft that drives the compression mechanism (30). The drive shaft (25) is positioned on the axis of the body portion (12) of the casing (11) and extends vertically inside the casing (11). The drive shaft (25) has a main shaft portion (26), a first eccentric portion (27), a second eccentric portion (28), and a sub-shaft portion (29).

[0043] The upper part of the main shaft (26) is fixed to the rotor (23). The first eccentric part (27) and the second eccentric part (28) are both provided at the lower part of the main shaft (26). The first eccentric part (27) is positioned above the second eccentric part (28). The first eccentric part (27) and the second eccentric part (28) are each formed to have a larger diameter than the main shaft (26). The first eccentric part (27) and the second eccentric part (28) are eccentric by a predetermined distance from the axis (AC) of the main shaft (26). The first eccentric part (27) and the second eccentric part (28) are eccentric to opposite sides of the axis (AC) of the drive shaft (25).

[0044] The drive shaft (25) is provided so as to pass through the compression mechanism (30). The portion of the main shaft (26) above the first eccentric portion (27) is rotatably supported by the front head (31) included in the compression mechanism (30). The sub-shaft (29) constitutes the portion of the drive shaft (25) below the second eccentric portion (28) and is rotatably supported by the rear head (43) included in the compression mechanism (30). In this example, the diameter Db of the sub-shaft (29) is approximately the same as the diameter Da of the main shaft (26) (Da=Db, or Da≈Db) (see Figure 3).

[0045] An oil passage (25a) is formed inside the drive shaft (25). The oil passage (25a) extends to the compression mechanism (30) and the sliding parts of the drive shaft (25). An oil supply pump (25b) is provided at the lower end of the drive shaft (25) (sub-shaft portion (29)). The oil supply pump (25b) is immersed in the oil in the oil reservoir (18) and transports oil as the drive shaft (25) rotates. The transported oil is supplied to the compression mechanism (30) and the sliding parts of the drive shaft (25) through the oil passage (25a).

[0046] <Compression mechanism> The compression mechanism (30) is a mechanism that draws in and compresses refrigerant and is located below the electric motor (21). The compression mechanism (30) consists of a front head (31), a first cylinder (35), a middle plate (38), a second cylinder (40), and a rear head (43). The front head (31), first cylinder (35), middle plate (38), second cylinder (40), and rear head (43) are made of metal such as cast iron. The front head (31) is an example of a first head. The rear head (43) is an example of a second head.

[0047] As shown in Figure 3, the compression mechanism (30) has a structure in which the front head (31), first cylinder (35), middle plate (38), second cylinder (40), and rear head (43) are stacked. The front head (31), first cylinder (35), middle plate (38), second cylinder (40), and rear head (43) are stacked in order from top to bottom and fixed together by bolts (70).

[0048] Specifically, a threaded hole (71) is formed in the front head (31). Through holes (72) are formed in the first cylinder (35), middle plate (38), second cylinder (40), and rear head (43) at positions corresponding to the threaded holes (71). Bolts (70) are inserted from the rear head (43) side and fasten the front head (31), first cylinder (35), middle plate (38), second cylinder (40), and rear head (43).

[0049] The front head (31) is an end plate member that forms the top cover of the first cylinder (35). The front head (31) is fixed to the body portion (12) of the casing (11). The front head (31) is stacked on top of the first cylinder (35). The front head (31) is positioned so as to cover the hollow portion of the first cylinder (35) from above. The front head (31) forms the upper surface of the first cylinder chamber (37).

[0050] A first bearing portion (32) is provided in the center of the front head (31). The first bearing portion (32) is formed in a cylindrical shape and protrudes upward. The first bearing portion (32) constitutes a sliding bearing. A first bearing hole (33) is formed in the first bearing portion (32). The first bearing hole (33) is a circular hole that penetrates the front head (31). The main shaft portion (26) of the drive shaft (25) is inserted through the first bearing hole (33).

[0051] A first annular groove (34) is formed on the end face of the front head (31) on the middle plate (38) side, in this example, on the lower surface. The first annular groove (34) extends in an annular shape along the periphery of the first bearing hole (33). The portion of the first bearing portion (32) between the first annular groove (34) and the first bearing hole (33) is configured to be elastically deformable. With this first bearing portion (32), the front head (31) rotatably supports the main shaft portion (26) of the drive shaft (25).

[0052] The first cylinder (35) is a thick-walled, roughly annular member. A first cylinder bore (36) is formed in the center of the first cylinder (35). The first cylinder bore (36) is a circular hole that penetrates the first cylinder (35) in the thickness direction. The first cylinder (35) is positioned so that the center line of the first cylinder bore (36) is oriented in the axial direction (up and down direction). The openings at both ends of the first cylinder bore (36) are closed by the front head (31) and the middle plate (38).

[0053] A first cylinder chamber (37) is formed inside the first cylinder (35). The first cylinder chamber (37) consists of a first cylinder bore (36) and is a space enclosed by the inner circumferential surface of the first cylinder (35), the lower surface of the front head (31), and the upper surface of the middle plate (38). The outer circumferential boundary of the first cylinder chamber (37) is defined by the inner circumferential surface of the first cylinder (35). The axial boundaries of the first cylinder chamber (37) are defined by the lower surface of the front head (31) and the upper surface of the middle plate (38).

[0054] The middle plate (38) is a roughly annular plate member that is sandwiched between the first cylinder (35) and the second cylinder (40). A shaft through hole (39) is formed in the center of the middle plate (38). The shaft through hole (39) is a circular hole that penetrates the middle plate (38) in the thickness direction. The portion of the main shaft portion (26) of the drive shaft (25) between the first eccentric portion (27) and the second eccentric portion (28) is inserted through the shaft through hole (39).

[0055] The middle plate (38) is positioned to cover the hollow portion (first cylinder bore (36)) of the first cylinder (35) from below. The middle plate (38) is positioned to cover the hollow portion (second cylinder bore (41)) of the second cylinder (40) from above. The upper surface of the middle plate (38) forms the lower surface of the first cylinder chamber (37). The lower surface of the middle plate (38) forms the upper surface of the second cylinder chamber (42).

[0056] The second cylinder (40) is a thick-walled, roughly annular member. A second cylinder bore (41) is formed in the center of the second cylinder (40). The second cylinder bore (41) is a circular hole that penetrates the second cylinder (40) in the thickness direction. The second cylinder (40) is positioned so that the center line of the second cylinder bore (41) is oriented in the axial direction (up and down direction). The openings at both ends of the second cylinder bore (41) are closed by the middle plate (38) and the rear head (43).

[0057] A second cylinder chamber (42) is formed inside the second cylinder (40). The second cylinder chamber (42) consists of a second cylinder bore (41) and is a space enclosed by the inner circumferential surface of the second cylinder (40), the lower surface of the middle plate (38), and the upper surface of the rear head (43). The outer circumferential boundary of the second cylinder chamber (42) is defined by the inner circumferential surface of the second cylinder (40). The axial lateral boundaries of the second cylinder chamber (42) are defined by the lower surface of the middle plate (38) and the upper surface of the rear head (43).

[0058] The rear head (43) is an end plate member that forms the lower cover of the second cylinder (40). The rear head (43) is stacked on the lower part of the second cylinder (40). The rear head (43) is positioned to cover the hollow portion (second cylinder bore (41)) of the second cylinder (40) from below. The rear head (43) forms the lower surface of the second cylinder chamber (42).

[0059] A second bearing portion (44) is provided in the center of the rear head (43). The second bearing portion (44) is formed in a cylindrical shape and protrudes downward. The second bearing portion (44) constitutes a sliding bearing. A second bearing hole (45) is formed in the second bearing portion (44). The second bearing hole (45) is a circular hole that penetrates the rear head (43). The sub-shaft portion (29) of the drive shaft (25) is inserted through the second bearing hole (45).

[0060] A second annular groove (46) is formed on the end face of the rear head (43) on the middle plate (38) side, in this example, on the upper surface. The second annular groove (46) extends in an annular shape along the periphery of the second bearing hole (45). The portion of the second bearing portion (44) between the second annular groove (46) and the second bearing hole (45) is configured to be elastically deformable. With this second bearing portion (44), the rear head (43) rotatably supports the sub-shaft portion (29) of the drive shaft (25).

[0061] As shown in Figure 4, the first cylinder (35) has a first bushing hole (47) and a first blade hole (48). The first bushing hole (47) and the second blade hole (58) penetrate the first cylinder (35) in the axial direction (thickness direction). The first bushing hole (47) and the first blade hole (48) are each formed in a substantially circular shape. The first bushing hole (47) opens radially into the first cylinder hole (36). The first blade hole (48) is located radially outside the first bushing hole (47) and communicates with the first bushing hole (47).

[0062] A pair of first bushes (49) are fitted into the first bush hole (47). Each first bush (49) is a semi-cylindrical member. The flat surfaces of the pair of first bushes (49) face each other with a gap between them. The pair of first bushes (49) are pivotable about the center line of the first bush hole (47). The pair of first bushes (49) restrict the rotation of the first piston (50) by sandwiching the first blade (52), which will be described later.

[0063] A first piston (50) is housed in the first cylinder chamber (37). The first piston (50) has a first roller (51) and a first blade (52). The first roller (51) is an annular member. The first eccentric portion (27) of the drive shaft (25) is fitted into the hollow portion of the first roller (51). The outer circumferential surface of the first roller (51) is in contact with the inner circumferential surface of the first cylinder (35) so as to allow it to slide in the circumferential direction. The first roller (51) rotates integrally with the first eccentric portion (27). A predetermined first gap (not shown) is formed between the first roller (51) and the lower surface of the front head (31) or the upper surface of the middle plate (38). The first gap is, for example, 10 μm or less.

[0064] The first blade (52) is provided on the outer circumferential surface of the first roller (51) and extends radially outward from the first roller (51). The first blade (52) is sandwiched between a pair of first bushes (49) so as to be able to move back and forth. The tip of the first blade (52) is housed in the first blade hole (48). In the first cylinder chamber (37), a first working space (53) for compressing the refrigerant is formed between the outer circumferential surface of the first roller (51) and the inner circumferential surface of the first cylinder (35). The first working space (53) is divided into a first low-pressure chamber and a first high-pressure chamber by the first blade (52).

[0065] A first intake passage (54) is formed in the first cylinder (35). The first intake passage (54) penetrates the first cylinder (35) radially. One end of the first intake passage (54) opens on the inner circumferential surface of the first cylinder (35) at a position adjacent to the first bush (49) (to the right of the first bush (49) in Figure 4) and communicates with the first low-pressure chamber. The other end of the first intake passage (54) opens on the outer circumferential surface of the first cylinder (35) and constitutes the inlet end. A first intake pipe (15) is connected to the inlet end of the first intake passage (54) (see Figure 3).

[0066] A first discharge passage (55) is formed in the front head (31). The first discharge passage (55) penetrates the front head (31) in the axial direction. One end of the first discharge passage (55) opens on the lower surface of the front head (31) at a position opposite to the first suction passage (54) relative to the first bush (49) (to the left of the first bush (49) in Figure 4) and communicates with the first high-pressure chamber. The other end of the first discharge passage (55) opens on the upper surface of the front head (31).

[0067] A first discharge valve (56) is provided on the upper surface of the front head (31). The first discharge valve (56) opens and closes the first discharge passage (55). The first discharge valve (56) is composed of, for example, a reed valve. The first discharge valve (56) is in a closed state, closing the first discharge passage (55) while the gas pressure in the first high-pressure chamber is lower than the gas pressure in the casing (11) (dome pressure). The first discharge valve (56) is in an open state, opening the first discharge passage (55) when the gas pressure in the first high-pressure chamber exceeds the dome pressure.

[0068] As shown in Figure 5, the second cylinder (40) has a second bushing hole (57) and a second blade hole (58). The second bushing hole (57) and the second blade hole (58) penetrate the second cylinder (40) in the axial direction (thickness direction). The second bushing hole (57) and the second blade hole (58) are each formed in a substantially circular shape. The second bushing hole (57) opens into the second cylinder hole (41). The second blade hole (58) is located outside the second bushing hole (57) in the radial direction of the second cylinder (40) and communicates with the second bushing hole (57).

[0069] A pair of second bushes (59) are fitted into the second bush hole (57). Each second bush (59) is a semi-cylindrical member. The flat surfaces of the pair of second bushes (59) face each other with a gap between them. The pair of second bushes (59) are pivotable about the center line of the second bush hole (57). The pair of second bushes (59) restrict the rotation of the second piston (60) by sandwiching the second blade (62), which will be described later.

[0070] A second piston (60) is housed in the second cylinder chamber (42). The second piston (60) has a second roller (61) and a second blade (62). The second roller (61) is an annular member. The second eccentric portion (28) of the drive shaft (25) is fitted into the hollow portion of the second roller (61). The outer circumferential surface of the second roller (61) is in contact with the inner circumferential surface of the second cylinder (40) so as to allow it to slide in the circumferential direction. The second roller (61) rotates integrally with the second eccentric portion (28). A predetermined second gap (not shown) is formed between the second roller (61) and the lower surface of the middle plate (38) or the upper surface of the rear head (43). The second gap is, for example, 10 μm or less.

[0071] The second blade (62) is provided on the outer circumferential surface of the second roller (61) and extends radially outward from the second roller (61). The second blade (62) is sandwiched between a pair of second bushes (59) so as to be able to move back and forth. The tip of the second blade (62) is housed in the second blade hole (58). In the second cylinder chamber (42), a second working space (63) for compressing the refrigerant is formed between the outer circumferential surface of the first roller (51) and the inner circumferential surface of the first cylinder (35). The second working space (63) is divided into a second low-pressure chamber and a second high-pressure chamber by the first blade (52).

[0072] A second intake passage (64) is formed in the second cylinder (40) and the rear head (43). The second intake passage (64) comprises a cylinder-side passage (65) formed in the second cylinder (40) and a head-side passage (66) formed in the rear head (43).

[0073] The cylinder-side passage (65) extends radially through the second cylinder (40). One end of the cylinder-side passage (65) opens at a position adjacent to the second bush (59) on the inner circumferential surface of the second cylinder (40) (the position to the right of the second bush (59) in Figure 5) and communicates with the second low-pressure chamber. The other end of the cylinder-side passage (65) opens on the rear head (43) side surface (the bottom surface in Figure 3) and constitutes the inlet end. The head-side passage (66) extends radially through the rear head (43). As shown in Figure 3, the head-side passage (66) has a first passage (66a) and a second passage (66b).

[0074] The first passage (66a) extends radially outward from the rear head (43). One end of the first passage (66a) opens to the outer circumferential surface of the rear head (43) and constitutes the inlet end. The second suction pipe (16) is connected to the inlet end of the first passage (66a). The second passage (66b) is provided on the other end side of the first passage (66a). The second passage (66b) extends upward in the axial direction from the first passage (66a). One end of the second passage (66b) opens to the upper surface of the rear head (43) and constitutes the outlet end. The outlet end of the second passage (66b) corresponds to the inlet end of the cylinder-side passage (65) and communicates with the second cylinder chamber (42) via the cylinder-side passage (65).

[0075] This configuration allows for a greater distance between the first suction pipe (15) and the second suction pipe (16) compared to the case where the second suction pipe (16) is connected to the second cylinder (40). The distance L1 between the center (C1) of the portion of the first suction pipe (15) that penetrates the body (12) of the casing (11) and the center (C2) of the portion of the second suction pipe (16) that penetrates the body (12) of the casing (11), and the distance L2 between the center (C3) of the first cylinder chamber (37) in the height direction and the center (C4) of the second cylinder chamber (42) in the height direction, satisfy the following relationship expressed by equation (1). L1>L2 ···(1)

[0076] As shown in Figure 5, a second discharge passage (67) is further formed in the rear head (43). The second discharge passage (67) penetrates the rear head (43) in the axial direction. One end of the second discharge passage (67) opens on the upper surface of the rear head (43) at a position opposite to the second suction passage (64) relative to the second bush (59) (to the left of the second bush (59) in Figure 5) and communicates with the second high-pressure chamber. The other end of the second discharge passage (67) opens on the lower surface of the rear head (43).

[0077] A second discharge valve (68) is provided on the underside of the rear head (43). The second discharge valve (68) opens and closes the second discharge passage (67). The second discharge valve (68) is composed of, for example, a reed valve. The second discharge valve (68) is in a closed state, closing the second discharge passage (67) while the gas pressure in the second high-pressure chamber is lower than the pressure inside the dome. The second discharge valve (68) is in an open state, opening the second discharge passage (67) when the gas pressure in the second high-pressure chamber exceeds the pressure inside the dome.

[0078] In the compression mechanism (30), the first piston (50) rotates eccentrically within the first cylinder chamber (37) as the drive shaft (25) rotates. As the eccentric rotation of the first piston (50) gradually increases the volume of the first low-pressure chamber, the refrigerant flowing through the first suction pipe (15) is drawn into the first low-pressure chamber from the first suction passage (54). As the first piston (50) continues to rotate eccentrically, the first low-pressure chamber is blocked from the first suction passage (54), and the blocked space constitutes the first high-pressure chamber.

[0079] As the eccentric rotation of the first piston (50) continues, the volume of the first high-pressure chamber gradually decreases, and the gas pressure inside the first high-pressure chamber increases. When the gas pressure inside the first high-pressure chamber exceeds the pressure inside the dome, the first discharge valve (56) opens, and the refrigerant in the first high-pressure chamber flows out of the compression mechanism (30) through the first discharge passage (55).

[0080] Furthermore, as the drive shaft (25) rotates, the second piston (60) rotates eccentrically within the second cylinder chamber (42) along with the eccentric rotation of the first piston (50). As the eccentric rotation of the second piston (60) gradually increases the volume of the second low-pressure chamber, the refrigerant flowing through the second suction pipe (16) is drawn into the second low-pressure chamber from the second suction passage (64). As the second piston (60) continues to rotate eccentrically, the second low-pressure chamber is blocked from the second suction passage (64), and the blocked space forms the second high-pressure chamber.

[0081] As the eccentric rotation of the second piston (60) further reduces the volume of the second high-pressure chamber, the gas pressure inside the second high-pressure chamber increases. When the gas pressure inside the second high-pressure chamber exceeds the pressure inside the dome, the second discharge valve (68) opens, and the refrigerant in the second high-pressure chamber flows out of the compression mechanism (30) through the second discharge passage (67).

[0082] The high-pressure refrigerant that has leaked out of the compression mechanism (30) flows upward through the internal space of the casing (11) and passes through the core cut (not shown) of the stator (22). The high-pressure refrigerant that has flowed above the electric motor (21) is then sent to the refrigerant circuit (1a) via the discharge pipe (17).

[0083] <accumulator> As shown in Figure 2, an accumulator (80) is connected to the upstream side of the rotary compressor (10). The accumulator (80) temporarily stores the refrigerant before it is drawn into the rotary compressor (10) and separates the liquid refrigerant and oil contained in the gaseous refrigerant into gas and liquid form. The accumulator (80) has a sealed container (81), an inlet pipe (82), a first outlet pipe (83), and a second outlet pipe (84).

[0084] The sealed container (81) is composed of a vertically elongated cylindrical member. The inlet pipe (82) is a pipe that allows refrigerant to flow into the sealed container (81). The inlet pipe (82) is connected to the top of the sealed container (81). The lower end of the inlet pipe (82) opens towards the upper part of the internal space of the sealed container (81). The upper end of the inlet pipe (82) is connected to the refrigerant circuit (1a).

[0085] The first outlet pipe (83) and the second outlet pipe (84) are pipes that allow refrigerant to flow out of the sealed container (81). The first outlet pipe (83) and the second outlet pipe (84) are connected to the lower part of the sealed container (81). The upper ends of the first outlet pipe (83) and the second outlet pipe (84) extend vertically within the sealed container (81) and open at a position near the upper part of the internal space of the sealed container (81).

[0086] The lower end of the first outlet pipe (83) extends downward from the lower end of the sealed container (81), then bends toward the first suction pipe (15) of the rotary compressor (10), and is connected to the first suction pipe (15). The lower end of the second outlet pipe (84) extends downward from the lower end of the sealed container (61), then bends toward the second suction pipe (16) of the rotary compressor (10), and is connected to the second suction pipe (16).

[0087] <Various designs related to the diameter or radius of the first and second cylinder chambers> The thickness Tm of the middle plate (38), the diameter Da of the main shaft (26), the eccentricity distance Le1 of the first piston (50), and the eccentricity distance Le2 of the second piston (60) are designed based on the diameter Ds1 of the first cylinder chamber (37) or the diameter Ds2 of the second cylinder chamber (42), respectively. As shown in Figure 3, the diameter Ds1 of the first cylinder chamber (37) and the diameter Ds2 of the second cylinder chamber (42) are identical. Hereafter, the diameter Ds1 of the first cylinder chamber (37) and the diameter Ds2 of the second cylinder chamber (42) will not be distinguished and will be referred to simply as diameter Ds.

[0088] Furthermore, the outer diameter of the first piston (50) and the outer diameter of the second piston (60) are the same. Also, the eccentricity distance Le1 of the first piston (50) and the eccentricity distance Le2 of the second piston (60) are the same. In the following, the eccentricity distance Le1 of the first piston (50) and the eccentricity distance Le2 of the second piston (60) will not be distinguished and will be referred to simply as the eccentricity distance Le. Here, "eccentricity distance Le1 of the first piston (50)" means the distance from the axis (AC) of the drive shaft (25) to the center (C5) of the first piston (50), and "eccentricity distance Le2 of the second piston (60)" means the distance from the axis (AC) of the drive shaft (25) to the center (C6) of the second piston (60).

[0089] The thickness Tm of the middle plate (38) is designed in relation to the diameters Ds of the first cylinder chamber (37) and the second cylinder chamber (42). Specifically, the diameters Ds of both the first cylinder chamber (37) and the second cylinder chamber (42), and the thickness Tm of the middle plate (38) satisfy the following relationship expressed in equation (2). 1 / 30 ≤ Tm / Ds ≤ 1 / 10 ... (2) The relationship expressed in equation (2) above was devised based on calculation formulas for the deflection and stress of a perforated disc.

[0090] As shown in Figure 6, if we consider a simplified model of the configuration of the first cylinder chamber (37) and the first piston (50), and the configuration of the second cylinder chamber (42) and the second piston (60), such that the first piston (50) is located in the center of the first cylinder chamber (37) and the second piston (60) is located in the center of the second cylinder chamber (42), then the amount of deflection y of the middle plate (38) can be calculated using the formula for deflection and stress of the perforated disc for the structural model shown in Figure 7. max This is expressed by the following equation (3).

number

[0091] The outer radius a of the middle plate (38) is half the diameter Ds of the first cylinder chamber (37) and the second cylinder chamber (42), and is therefore expressed as a = Ds / 2. Based on this, by rearranging equation (3) above, we obtain the following equation (4).

number

[0092] The left side of equation (4) above is the index value y, which indicates the amount of deflection of the middle plate (38). max Figure 8 shows the relationship between / Tm and Ds / Tm, which appears on the right-hand side of equation (4) above, as a graph. Note that the data in Figure 8 was calculated assuming the middle plate (38) is made of cast iron (E=110GPa) and the differential pressure between the first cylinder chamber (37) and the second cylinder chamber (42) is 3MPa (P=3MPa). As shown in Figure 8, the index value y indicates the amount of deflection of the middle plate (38). max The value of / Tm increases as the value of Ds / Tm increases.

[0093] Furthermore, when calculating the case where the diameters Ds of the first cylinder chamber (37) and the second cylinder chamber (42) are 50 mm, the eccentricity distance Le of the first piston (50) and the eccentricity distance Le of the second piston (60) are 5 mm, and k = 0.00077, as shown in Figure 9, if the function Ds / Tm is in the range of 10 or more and 30 or less, the amount of deflection of the middle plate (38) can be made sufficiently small compared to the first gap and the second gap (10 μm or less). From this, the diameters Ds of both the first cylinder chamber (37) and the second cylinder chamber (42), and the thickness Tm of the middle plate (38) are designed to satisfy the relationship expressed in equation (2) above (1 / 30 ≤ Tm / Ds ≤ 1 / 10).

[0094] The diameter Da of the main shaft (26) is designed in relation to the diameters Ds of the first cylinder chamber (37) and the second cylinder chamber (42). Specifically, the diameters Ds of both the first cylinder chamber (37) and the second cylinder chamber (42), and the diameter Da of the main shaft (26) satisfy the relationship expressed by equation (5) below. As a result, the diameter Da of the main shaft (26) in this example is designed to be relatively small compared to the diameters Ds of the first cylinder chamber (37) and the second cylinder chamber (42). Da ≤ Ds × 0.35 ···(5)

[0095] The eccentricity distance Le of the first piston (50) and the second piston (60) is designed in relation to the radius Rs of the first cylinder chamber (37) and the second cylinder chamber (42). Specifically, the radius Rs of both the first cylinder chamber (37) and the second cylinder chamber (42), and the eccentricity distance Le of the first piston (50) and the second piston (60) satisfy the following relationship expressed in equation (6). Le / Rs ≤ 0.25 ···(6)

[0096] As described above, the outer radius a of the middle plate (38) is given by a = Ds / 2, and the inner radius b of the middle plate (38) is given by b = ae. Based on this, by rearranging equation (6) above, we obtain the following equation (7). a / b ≤ 1.333 ···(7) In this case, the coefficient k in equation (3) above can be considered to be the same as in the case where a / b = 1.25 in a known table showing the relationship between the coefficient k and a / b, and can be thought of as 0.00077. Furthermore, by rearranging equation (4) above, the following equation (8) can be obtained.

number

[0097] Then, in equation (8) above, if we assume the data in Figure 8 is the same, with E=110 GPa and P=3 MPa, then from equation (9) above, y max The range of / Tm is expressed by the following equation (10). 0.000013≦y max / Tm≦0.0001 ···(10) Therefore, by designing the ratio (Le / Rs) of the radii Rs of the first cylinder chamber (37) and the second cylinder chamber (42) to the eccentric distances Le of the first piston (50) and the second piston (60) to an appropriate range so as to satisfy equation (6) above, the deflection of the middle plate (38) can be suppressed to 1 / 1000 or less of the thickness Tm.

[0098] -Features of the Embodiment- In this embodiment of the rotary compressor (10), the thickness Tm of the middle plate (38) is 1 / 30 to 1 / 10 of the diameter Ds of both the first cylinder chamber (37) and the second cylinder chamber (42). When the thickness Tm of the middle plate (38) is 1 / 30 or more of the diameter Ds of the first cylinder chamber (37) and the second cylinder chamber (42), deflection of the middle plate (38) due to the pressure of the fluid compressed in the first cylinder chamber (37) and the second cylinder chamber (42) can be suitably suppressed. Furthermore, when the thickness Tm of the middle plate (38) is 1 / 10 or less of the diameter Ds of the first cylinder chamber (37) and the second cylinder chamber (42), the distance between the front head (31) and the rear head (43) can be reduced. This suppresses deflection of the drive shaft (25). Therefore, the reliability of the rotary compressor (10) when the diameter of the drive shaft (25) is reduced can be improved.

[0099] In the rotary compressor (10) of this embodiment, the distance L1 between the two centers (C1, C2) of the portions of the first suction pipe (15) and the second suction pipe (16) that penetrate the casing (11) is greater than the distance L2 between the two centers (C3, C4) in the height direction of the first cylinder chamber (37) and the second cylinder chamber (42). This ensures the strength between the portions of the casing (11) through which the first suction pipe (15) and the second suction pipe (16) penetrate.

[0100] In the rotary compressor (10) of this embodiment, the ratio (Le / Rs) of the eccentricity distance Le of the first piston (50) to the radius Rs of the first cylinder chamber (37), and the ratio (Le / Rs) of the eccentricity distance Le of the second piston (60) to the radius Rs of the second cylinder chamber (42) are both 0.25 or less. As a result, based on the calculation formula for the deflection and stress of the perforated disc, the amount of deflection of the middle plate (38) can be suitably suppressed and made minute relative to the thickness of the middle plate (38). This is advantageous in improving the reliability of the rotary compressor (10).

[0101] In this embodiment of the rotary compressor (10), the first suction pipe (15) is connected to the first cylinder (35), and the second suction pipe (16) is connected to the rear head (43). This configuration specifically allows for a setup in which the distance L1 between the two centers (C1, C2) of the portions of the first suction pipe (15) and the second suction pipe (16) that penetrate the casing (11) is greater than the distance L2 between the two centers (C3, C4) in the height direction of the first cylinder chamber (37) and the second cylinder chamber (42). Furthermore, since the first suction pipe (15) is connected to the first cylinder (35), the flow path of the refrigerant sent to the compression mechanism (30) via the first suction pipe (15) to the first cylinder chamber (37) is shortened compared to the case where the first suction pipe (15) is connected to the front head (31), thereby reducing the pressure loss of the refrigerant.

[0102] In the rotary compressor (10) of this embodiment, the diameter Da of the main shaft portion (26) of the drive shaft (25) supported by the front head (31) is 0.35 times or less the diameter Ds of the first cylinder chamber (37) or the second cylinder chamber (42). When the diameter Da of the main shaft portion (26) is relatively small in this way, friction loss between the main shaft portion (26) and the front head (31) can be reduced. This makes it possible to increase the compression efficiency of the rotary compressor (10). On the other hand, a drive shaft (25) having a relatively small diameter main shaft portion (26) is prone to deflection during operation of the rotary compressor (10). In a rotary compressor (10) equipped with such a drive shaft (25), the technology of this disclosure is particularly effective because it can suppress the deflection of the drive shaft (25).

[0103] In this embodiment of the rotary compressor (10), a first annular groove (34) is formed on the end face of the front head (31) on the middle plate (38) side. This allows the first bearing portion (32) of the front head (31) to be configured to be elastically deformable between the first annular groove (34) and the first bearing hole (33). In addition, a second annular groove (46) is formed on the end face of the rear head (43) on the middle plate (38) side. This allows the second bearing portion (44) of the rear head (43) to be elastically deformable between the second annular groove (46) and the second bearing hole (45).

[0104] When the rotary compressor (10) is in operation, the pressure of the refrigerant compressed in the first cylinder chamber (37) acts on the first piston (50), and the pressure of the refrigerant compressed in the second cylinder chamber (42) acts on the second piston (60). The resulting compression load is applied to the drive shaft (25), causing the drive shaft (25) to deflect radially. When the drive shaft (25) deflects, the first bearing section (32) and the second bearing section (44) elastically deform toward the first annular groove (34) side or the second annular groove (46) side in accordance with the deflection of the drive shaft (25), and deflect together with the drive shaft (25). This prevents the drive shaft (25) from making strong uneven contact with the front head (31) or rear head (43), and reduces wear between the first bearing section (32) and the second bearing section (44) and the drive shaft (25).

[0105] In the rotary compressor (10) of this embodiment, the maximum rotational speed of the drive shaft (25) is 120 rps or higher, which is relatively high. The faster the rotation of the drive shaft (25) becomes, the greater the deflection of the drive shaft (25) tends to be. In a rotary compressor (10) operated at such a relatively high rotational speed, the technology of this disclosure is particularly effective because it can suppress the deflection of the drive shaft (25).

[0106] The refrigeration system (1) of this embodiment includes a rotary compressor (10). In the rotary compressor (10), the reliability is improved when the diameter of the drive shaft (25) of the rotary compressor (10) is reduced. By including the rotary compressor (10), the energy efficiency can be improved while maintaining the reliability of the refrigeration system (1) by increasing the compression efficiency through the reduction in the diameter of the drive shaft (25).

[0107] -First variation- In this first modified rotary compressor (10), as shown in Figure 10, the main shaft portion (26) and the sub-shaft portion (29) of the drive shaft (25) are designed to have different diameters Da and Db. Specifically, in the drive shaft (25), the diameter Da of the main shaft portion (26) and the diameter Db of the sub-shaft portion (29) satisfy the following relationship expressed by equation (11). Dand <Da ···(11)

[0108] In this first modified rotary compressor (10), the diameter Db of the sub-shaft portion (29) supported by the rear head (43) of the drive shaft (25) is smaller than the diameter Da of the main shaft portion (26) supported by the front head (31). When the diameter Db of the sub-shaft portion (29) is smaller than the diameter Da of the main shaft portion (26), friction loss between the sub-shaft portion (29) and the rear head (43) can be reduced compared to when the diameter Db of the sub-shaft portion (29) is the same as the diameter Da of the main shaft portion (26). This is advantageous for increasing the compression efficiency of the rotary compressor (10).

[0109] -Second variation- In this second modified rotary compressor (10), as shown in Figure 11, the connection points of the first suction pipe (15) and the second suction pipe (16) differ from those of the above embodiment. Specifically, the first suction pipe (15) is connected to the front head (31), and the second suction pipe (16) is connected to the second cylinder (40). In this example, the first suction passage (54) is composed of a cylinder-side passage (65) and a head-side passage (66) similar to the second suction passage (64) in the above embodiment. The second suction passage (64) is formed similarly to the first suction passage (54) in the above embodiment.

[0110] -Third variation- In this third modified rotary compressor (10), as shown in Figure 12, the connection point of the first suction pipe (15) differs from that of the above embodiment. Specifically, the first suction pipe (15) is connected to the front head (31), and the second suction pipe (16) is connected to the rear head (43). In this example, the first suction pipe (15) is composed of a cylinder-side passage (65) and a head-side passage (66) similar to the second suction passage (64) in the above embodiment. Similarly, the second suction pipe (16) is also composed of a cylinder-side passage (65) and a head-side passage (66) similar to those in the above embodiment.

[0111] Other embodiments As shown in Figure 13, the compression mechanism (30) of the rotary compressor (10) in the above embodiment may be configured as a rolling piston type in which the first blade (52) of the first piston (50) is formed separately from the first roller (51). In this compression mechanism (30), a flat plate-shaped first blade (52) is fitted into a first blade groove (90) extending radially in the first cylinder (35) so as to be able to move back and forth, and the first bush (49) is omitted. The first blade (52) is pressed against the outer circumferential surface of the first roller (51) by a spring (91). The tip of the first blade (52) is in contact with the outer circumferential surface of the first roller (51) so as to be able to slide. These things may be the same for the second piston (60).

[0112] The diameter Ds1 of the first cylinder chamber (37) and the diameter Ds2 of the second cylinder chamber (42) may be different from each other. In this case, the diameter Ds is defined as the smaller of at least the diameter Ds1 of the first cylinder chamber (37) and the diameter Ds2 of the second cylinder chamber (42), and this diameter Ds satisfies the relationship expressed in equation (2) above (1 / 30 ≤ Tm / Ds ≤ 1 / 10). In short, it is sufficient that the diameters Ds(Ds1, Ds2) or the smaller diameter Ds of both the first cylinder chamber (37) and the second cylinder chamber (42), and the thickness Tm of the middle plate (38), satisfy the relationship expressed in equation (2) above.

[0113] The first annular groove (34) does not need to be formed on the lower surface of the front head (31). Similarly, the second annular groove (46) does not need to be formed on the upper surface of the rear head (43). In other words, either the first annular groove (34) or the second annular groove (46) may be formed on the end face of one of the front head (31) or rear head (43) on the middle plate (38) side, and only one of the first bearing portion (32) or the second bearing portion (44) may be configured to be partially elastically deformable.

[0114] The compression mechanism (30) may be configured as a two-stage compression type in which the refrigerant compressed in one of the first cylinder chambers (37) and the second cylinder chamber (42) is further compressed in the other. The compression mechanism (30) may also be configured to include three or more cylinders. For example, the compression mechanism (30) may have a structure in which a front head (31), a first cylinder (35), a first middle plate corresponding to a middle plate (38), a second cylinder (40), a second middle plate, a third cylinder, and a rear head (43) are stacked.

[0115] While embodiments and variations have been described above, it will be understood that a variety of modifications to the form and details are possible without departing from the spirit and scope of the claims. Furthermore, these embodiments and variations may be combined or substituted as appropriate, as long as they do not impair the functions covered by this disclosure. [Industrial applicability]

[0116] As described above, this disclosure is useful for rotary compressors and refrigeration systems. [Explanation of symbols]

[0117] 1. Refrigeration equipment 10 Rotary Compressor 11 Casing 15 1st suction pipe 16 2nd suction pipe 21 Electric motor 25 Drive shaft 26 Main shaft 29 Subshaft part 31 Front head (first head) 33 First bearing hole (bearing hole) 34. First ring groove (ring groove) 35. First Cylinder 37. First Cylinder Chamber 38 Middle Plate 40 Second Cylinder 42 Second Cylinder Chamber 43 Rear Head (Second Head) 45. Second bearing hole (bearing hole) 46. ​​Second Ring Groove (Ring Groove) 50 First piston 60. Second piston AC axis center

Claims

1. A compression mechanism (30) having a structure in which a first head (31), a first cylinder (35), a middle plate (38), a second cylinder (40), and a second head (43) are stacked, The compression mechanism (30) is provided with a drive shaft (25) that penetrates in the stacking direction and is rotatably supported by the first head (31) and the second head (43), A casing (11) housing the compression mechanism (30) and the drive shaft (25), The device comprises a first suction pipe (15) and a second suction pipe (16) that penetrate the casing (11) and are connected to the compression mechanism (30), A space is formed inside the casing (11) that is filled with high-pressure fluid discharged from the compression mechanism (30). A first cylinder chamber (37) is formed inside the first cylinder (35), defined by the first head (31) and the middle plate (38). The first cylinder chamber (37) houses a first piston (50) that rotates eccentrically in conjunction with the rotation of the drive shaft (25), and a first working space (53) for compressing fluid is formed therein. The first working space (53) is formed only on the outer circumference side of the first piston (50), The first piston (50) rotates eccentrically in the first cylinder chamber (37) to draw low-pressure fluid into the first working space (53) through the first suction pipe (15), compresses the low-pressure fluid drawn into the first working space (53) to make it high-pressure fluid, and then discharges it to the outside of the compression mechanism (30). A second cylinder chamber (42) is formed inside the second cylinder (40), defined by the middle plate (38) and the second head (43). The second cylinder chamber (42) houses a second piston (60) that rotates eccentrically in conjunction with the rotation of the drive shaft (25), and a second working space (63) for compressing fluid is formed therein. The second working space (63) is formed only on the outer circumference side of the second piston (60), The second piston (60) rotates eccentrically in the second cylinder chamber (42), drawing low-pressure fluid into the second working space (63) through the second suction pipe (16), compressing the low-pressure fluid drawn into the second working space (63) to a high-pressure fluid, and then discharging it to the outside of the compression mechanism (30). The diameters Ds of both the first cylinder chamber (37) and the second cylinder chamber (42), or the smaller of the two diameters Ds, and the thickness Tm of the middle plate (38) satisfy the relationship expressed by 1 / 30 ≤ Tm / Ds ≤ 1 / 10. The first suction tube (15) is connected to the first head (31), or The second suction tube (16) is connected to the second head (43), Rotary compressor.

2. In the rotary compressor according to claim 1, The distance L1 between the center (C1) of the portion of the first intake pipe (15) that penetrates the casing (11) and the center (C2) of the portion of the second intake pipe (16) that penetrates the casing (11), and the distance L2 between the center (C3) of the first cylinder chamber (37) in the height direction and the center (C4) of the second cylinder chamber (42) in the height direction, satisfy the relationship expressed as L1 > L2. Rotary compressor.

3. In the rotary compressor according to claim 1, The first piston (50) and the second piston (60) are eccentric with respect to the axis (AC) of the drive shaft (25), The eccentricity distance Le of the first piston (50) or the second piston (60) with respect to the diameter Ds that satisfies the aforementioned relation, the radius Rs of the first cylinder chamber (37) formed inside the first piston (50), or the radius Rs of the second cylinder chamber (42) formed inside the second piston (60) that satisfies the relation expressed as Le / Rs ≤ 0.

25. Rotary compressor.

4. In the rotary compressor according to claim 1, The first suction tube (15) is connected to the first head (31), and the second suction tube (16) is connected to the second cylinder (40), or The first suction tube (15) is connected to the first cylinder (35), and the second suction tube (16) is connected to the second head (43). Rotary compressor.

5. In the rotary compressor according to claim 1, The drive shaft (25) is further connected to an electric motor (21), The electric motor (21) is positioned between it and the first cylinder (35) via the first head (31), The drive shaft (25) has a main shaft portion (26) supported by the first head (31), The diameter Ds that satisfies the above relation, and the diameter Da of the main shaft portion (26) satisfy the relation expressed as Da ≤ Ds × 0.

35. Rotary compressor.

6. In the rotary compressor according to claim 1, The drive shaft (25) is further connected to an electric motor (21), The electric motor (21) is positioned between it and the first cylinder (35) via the first head (31), The drive shaft (25) has a main shaft portion (26) supported by the first head (31) and a sub-shaft portion (29) supported by the second head (43), The diameter Da of the main shaft portion (26) and the diameter Db of the sub-shaft portion (29) satisfy the relationship expressed as Db < Da. Rotary compressor.

7. In the rotary compressor according to claim 1, The first head (31) and the second head (43) are formed with bearing holes (33, 45) through which the drive shaft (25) is inserted. An annular groove (34, 46) is formed on the end face of the first head (31) or the second head (43) on the middle plate (38) side, extending along the periphery of the bearing hole (33, 45). Rotary compressor.

8. In the rotary compressor according to claim 1, A rotary compressor in which the maximum rotational speed of the drive shaft (25) is 120 rpm or more.

9. A rotary compressor (10) according to any one of claims 1 to 8, Refrigeration equipment.

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