Refrigerant compressor, refrigeration device, and air-conditioning system

Abstract

A refrigerant compressor (10) uses carbon dioxide as a refrigerant. A casing (13) houses a crankshaft (25), a motor (21), and a compression mechanism (30). The crankshaft (25) is provided with, at a lower end portion thereof, an oil supply mechanism (38) having a suction port (39) through which oil stored in a lower end portion of the casing (13) is drawn. A displacement volume Vcc [cc] per rotation of the compression mechanism (30) and a distance L1 [mm] between the suction port (39) and a lower end of a member joined to the casing (13), among members constituting the compression mechanism (30), satisfy the following condition: L1 / Vcc>13.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a refrigerant compressor, a refrigeration apparatus, and an air-conditioning system.BACKGROUND ART

[0002] Patent Document 1 discloses that when spaces having different pressures, such as a primary space and a secondary space, exist inside a casing of a rotary compressor, pressure fluctuations may be caused by space resonance, moving a crankshaft in an axial direction, and as a result, the crankshaft may collide with a head, generating noise.

[0003] In Patent Document 1, the dimensions of the components of the rotary compressor are designed, or its operation is adjusted, so that the operation frequency is (resonance frequency / 1.2) or less, thereby reducing noise generated by the vertical vibration of the crankshaft.CITATION LISTPATENT DOCUMENT

[0004] [PATENT DOCUMENT 1] Japanese Unexamined Patent Publication No. H10-089252SUMMARY OF THE INVENTIONTECHNICAL PROBLEM

[0005] The inventors of the present application have found that when carbon dioxide is used as a refrigerant, the mass of the discharged refrigerant is larger than that of other refrigerants, and therefore, the excitation force that causes pressure fluctuations increases, making it more likely that noise is caused by the vertical vibration of the crankshaft.

[0006] An object of the present disclosure is to reduce the collision of a crankshaft with a head, thereby reducing noise, when carbon dioxide is used as a refrigerant.SOLUTION TO THE PROBLEM

[0007] A first aspect of the present disclosure is directed to a refrigerant compressor using carbon dioxide as a refrigerant, the refrigerant compressor including: a crankshaft (25) extending along a first direction and having an eccentric portion (27); a motor (21) configured to rotate the crankshaft (25); a compression mechanism (30) coupled to the crankshaft (25) and configured to be driven by the crankshaft (25); and a casing (13) which houses the crankshaft (25), the motor (21), and the compression mechanism (30), and in which a primary space (11) below the motor (21) and a secondary space (12) above the motor (21) are formed, the compression mechanism (30) including: a first head (31) rotatably supporting the crankshaft (25); a cylinder (70) disposed adjacent to the first head (31) and including a cylinder chamber (71); and a roller (76) fixed to the eccentric portion (27) and configured to eccentrically rotate in the cylinder chamber (71), the eccentric portion (27) having an upper surface overlapping with a part of a lower surface of the first head (31) when viewed from the first direction, the crankshaft (25) being provided with, at a lower end portion thereof, an oil supply mechanism (38) including a suction port (39) through which oil stored in a lower end portion of the casing (13) is drawn, a displacement volume Vcc [cc] per rotation of the compression mechanism (30) and a distance L1 [mm] between the suction port (39) and a lower end of a member joined to the casing (13), among members constituting the compression mechanism (30), satisfying the following condition: L1 / Vcc > 13.

[0008] According to the first aspect, by increasing the distance L1 so as to satisfy the condition described above and thereby bringing the excitation position of the resonance closer to the node, pressure fluctuations caused by the resonance are decreased, which can reduce the collision of the crankshaft (25) with the first head (31), thereby reducing noise.

[0009] A second aspect of the present disclosure is an embodiment of the refrigerant compressor of the first aspect. In the second aspect, the compression mechanism (30) is provided with a discharge port (63) through which compressed refrigerant is discharged to the primary space (11), and a distance L0 [mm] between an upper end of the secondary space (12) and the suction port (39), a distance L [mm] between the discharge port (63) and a midpoint between the upper end of the secondary space (12) and the suction port (39), and a total weight M [kg] of a rotor (23) of the motor (21) and the crankshaft (25) satisfy the following condition: Vcc × sin πL / L 0 / M ≤ 0.90 .

[0010] According to the second aspect, by satisfying the condition described above, pressure fluctuations caused by the resonance can be decreased, thereby reducing noise caused by the collision of the crankshaft (25) with the first head (31).

[0011] Specifically, the smaller the displacement volume Vcc is, the smaller the discharge amount of the refrigerant becomes and the smaller the excitation force of the resonance becomes. The closer the discharge port (63), serving as the excitation position of the resonance, is to the node of the resonance, the less likely the resonance is to be excited. The greater the total weight M of the rotor (23) and the crankshaft (25) is, the less likely the crankshaft (25) is to move vertically. The greater the parameter L1 / Vcc becomes, the smaller the parameter Vcc × sin(πL / L0) becomes.

[0012] A third aspect of the present disclosure is an embodiment of the refrigerant compressor of the second aspect. In the third aspect, the following condition is satisfied: Vcc × sin(πL / L0) / M ≤ 0.86.

[0013] According to the third aspect, it is possible to further reduce the vertical movement of the crankshaft (25) caused by pressure fluctuations due to the resonance, thereby reducing noise generation.

[0014] A fourth aspect of the present disclosure is an embodiment of the refrigerant compressor of any one of the first to third aspects. In the fourth aspect, the cylinder (70) includes: a first cylinder (40) including a first cylinder chamber (41); and a second cylinder (50) including a second cylinder chamber (51), and the roller (76) includes: a first roller (46) housed in the first cylinder chamber (41); and a second roller (56) housed in the second cylinder chamber (51).

[0015] According to the fourth aspect, satisfying the above-described conditions can help reduce pressure fluctuations caused by the resonance, thereby reducing noise generation, even in a large-volume, multi-cylinder refrigerant compressor including the first cylinder (40) and the first roller (46), and the second cylinder (50) and the second roller (56), which tends to generate noise easily.

[0016] A fifth aspect of the present disclosure is an embodiment of the refrigerant compressor of any one of the first to fourth aspects. In the fifth aspect, a maximum number of revolutions of a rotor (23) of the motor (21) is 100 rps or higher.

[0017] According to the fifth aspect, the maximum number of revolutions of the rotor (23) is set to 100 rps or higher, which lowers the oil level and the resonance frequency. Therefore, even if the rotor (23) is rotated at a high speed and a collision with the resonance occurs, noise generation can be reduced.

[0018] A sixth aspect of the present disclosure is directed to a refrigeration apparatus including the refrigerant compressor (10) of any one of the first to fifth aspects.

[0019] According to the sixth aspect, a refrigeration apparatus including the refrigerant compressor (10) can be provided.

[0020] A seventh aspect of the present disclosure is directed to an air-conditioning system including the refrigeration apparatus (1) of the sixth aspect, the refrigeration apparatus (1) being an air-conditioning apparatus configured to condition air in a predetermined target space.

[0021] According to the seventh aspect, an air-conditioning system including the refrigeration apparatus (1) serving as an air-conditioning apparatus can be provided.BRIEF DESCRIPTION OF THE DRAWINGS

[0022] [FIG. 1] FIG. 1 is a refrigerant circuit diagram illustrating a configuration of an air-conditioning system of an embodiment. [FIG. 2] FIG. 2 is a vertical sectional view illustrating a configuration of a refrigerant compressor. [FIG. 3] FIG. 3 is a transverse sectional view illustrating a configuration of a first cylinder and a first roller. [FIG. 4] FIG. 4 is a transverse sectional view illustrating a configuration of a second cylinder and a second roller. [FIG. 5] FIG. 5 is a diagram showing a waveform of pressure fluctuations caused by space resonance. [FIG. 6] FIG. 6 is a graph showing the relationship between the displacement volume Vcc and the distance L1. [FIG. 7] FIG. 7 is a graph showing the relationship between the total weight M and the parameter Vcc × sin(πL / L0). [FIG. 8] FIG. 8 is a graph showing the relationship between the number of revolutions of a rotor and the differential pressure load. DESCRIPTION OF EMBODIMENTS

[0023] As shown in FIG. 1, an air-conditioning system (100) includes a refrigeration apparatus (1) serving as an air-conditioning apparatus that conditions air in a predetermined target space. The refrigeration apparatus (1) includes a refrigerant circuit (1a) filled with a refrigerant. In the present embodiment, carbon dioxide is used as the refrigerant.

[0024] The refrigerant circuit (1a) includes a refrigerant compressor (10), a radiator (3), a decompression mechanism (4), and an evaporator (5). The decompression mechanism (4) is, for example, an expansion valve. The refrigerant circuit (1a) performs a vapor compression refrigeration cycle.

[0025] The refrigeration apparatus (1) may be any of a cooling-only apparatus, a heating-only apparatus, or an air-conditioning apparatus switchable between cooling and heating. In this case, the refrigeration apparatus (1) has a switching mechanism (e.g., a four-way switching valve) for switching the directions of circulation of the refrigerant.

[0026] As shown in FIG. 2, the refrigerant compressor (10) includes a casing (13), a drive mechanism (20), and a compression mechanism (30). The drive mechanism (20) and the compression mechanism (30) are housed in the casing (13).

[0027] The casing (13) is configured as a vertically long cylindrical closed container. An oil reservoir (18) is provided at the bottom of the casing (13). The oil reservoir (18) stores oil for lubricating sliding portions of the compression mechanism (30) and a crankshaft (25).

[0028] Suction pipes (15) and a discharge pipe (16) are inserted through and fixed to a barrel of the casing (13). An accumulator (80) is connected to the suction pipes (15). The accumulator (80) temporarily stores the refrigerant to be sucked into the refrigerant compressor (10) and performs gas-liquid separation for the liquid refrigerant and oil contained in the gas refrigerant. The discharge pipe (16) communicates with a secondary space (12) of the casing (13), which will be described later.<Drive Mechanism>

[0029] The drive mechanism (20) includes a motor (21) and the crankshaft (25). The motor (21) is disposed above the compression mechanism (30). The motor (21) includes a stator (22) and a rotor (23).

[0030] The stator (22) is fixed to the inner peripheral surface of the casing (13). The rotor (23) extends vertically through the interior of the stator (22). The crankshaft (25) is fixed inside the axial center of the rotor (23). The crankshaft (25) is driven to rotate together with the rotor (23) when the motor (21) is energized.

[0031] A primary space (11) and the secondary space (12) are formed inside the casing (13). The primary space (11) is a space below the motor (21). The secondary space (12) is a space above the motor (21).

[0032] The crankshaft (25) is arranged on the axis of the casing (13). The crankshaft (25) extends along a first direction (the vertical direction in FIG. 2). An oil supply mechanism (38) is provided at a lower end portion of the crankshaft (25). The oil supply mechanism (38) has a suction port (39). The oil supply mechanism (38) draws oil stored in the oil reservoir (18) through the suction port (39) and conveys the oil. The conveyed oil is supplied to the sliding portions of the compression mechanism (30) and the crankshaft (25) through an oil passage (29) inside the crankshaft (25).

[0033] Although the crankshaft (25) and the oil supply mechanism (38) are separate components in the present embodiment, the crankshaft (25) and the oil supply mechanism (38) may be integrated with each other.

[0034] The crankshaft (25) includes a main shaft portion (26), a first eccentric portion (27), and a second eccentric portion (28). An upper portion of the main shaft portion (26) is fixed to the rotor (23) of the motor (21). The first eccentric portion (27) is located above the second eccentric portion (28). The axes of the first eccentric portion (27) and the second eccentric portion (28) are eccentric from the axis of the main shaft portion (26) by a predetermined amount.

[0035] Part of the main shaft portion (26) above the first eccentric portion (27) is rotatably supported by a front head (31) described later. Part of the main shaft portion (26) below the second eccentric portion (28) is rotatably supported by a rear head (33) described later.<Compression Mechanism>

[0036] In the example shown in FIG. 2, the compression mechanism (30) is a two-cylinder rotary fluid machine. The compression mechanism (30) is disposed below the motor (21). The compression mechanism (30) is coupled to and driven by the crankshaft (25).

[0037] The refrigerant compressor of the present embodiment is of a type in which each roller eccentrically rotates with a vane connected to a specific position of an outer peripheral portion of the roller. The refrigerant compressor may be a so-called swing compressor in which a vane and a roller are integrally formed, or may be a hinged-vane compressor in which a vane, as a separate component from a roller, is rotatably fixed to an end portion of the roller. The following will describe the compression mechanism (30) in which each vane and the corresponding roller are integrally formed.

[0038] The compression mechanism (30) includes a cylinder (70) having a cylinder chamber (71). The cylinder chamber (71) houses a roller (76). The cylinder chamber (71) includes a first cylinder chamber (41) and a second cylinder chamber (51). The cylinder (70) includes a first cylinder (40) having the first cylinder chamber (41) and a second cylinder (50) having the second cylinder chamber (51). The roller (76) includes a first roller (46) housed in the first cylinder chamber (41) and a second roller (56) housed in the second cylinder chamber (51).

[0039] The compression mechanism (30) includes the front head (31) as a first head, the first cylinder (40), a middle plate (32), the second cylinder (50), and the rear head (33).

[0040] The front head (31), the first cylinder (40), the middle plate (32), the second cylinder (50), and the rear head (33) are stacked in this order from top to bottom and fixed with a fastening bolt (35).

[0041] The front head (31) is fixed to the casing (13) via a mounting plate (36). The front head (31) may be joined to the casing (13) without using the mounting plate (36). Furthermore, instead of the front head (31), any of the first cylinder (40), the second cylinder (50), and the rear head (33) may be joined to the casing (13).

[0042] The front head (31) is stacked on top of the first cylinder (40). The front head (31) is arranged to cover the first cylinder chamber (41) of the first cylinder (40) from above.

[0043] The main shaft portion (26) of the crankshaft (25) is inserted through a central portion of the front head (31). The front head (31) rotatably supports the crankshaft (25). The front head (31) has a first discharge passage (49) (see FIG. 3) extending therethrough in the axial direction. The upper surface of the first eccentric portion (27) overlaps with a part of the lower surface of the front head (31) when viewed from the first direction (i.e., the axial direction of the crankshaft (25)).

[0044] A first muffler (61) and a second muffler (65) are provided on an upper surface of the front head (31). The first muffler (61) covers the first discharge passage (49) (see FIG. 3) so as to define a first muffler space (62). The second muffler (65) is disposed in the first muffler space (62). The second muffler (65) defines a second muffler space (66) between itself and the front head (31). A second discharge passage (59) (see FIG. 4) communicates with the second muffler space (66).

[0045] The first muffler (61) has a first discharge port (63). The first discharge port (63) communicates with the first muffler space (62) and the primary space (11). The compressed refrigerant discharged from the first discharge passage (49) is discharged to the primary space (11) through the first discharge port (63).

[0046] The second muffler (65) has a second discharge port (67). The second discharge port (67) communicates with the second muffler space (66) and the first muffler space (62). The compressed refrigerant discharged from the second discharge passage (59) is discharged to the first muffler space (62) through the second discharge port (67).

[0047] The first cylinder (40) is configured as a flat and substantially annular member. The first cylinder (40) is disposed adjacent to the front head (31). As shown in FIG. 3, the first cylinder (40) includes the first cylinder chamber (41), a first suction passage (42), and a first vane chamber (43).

[0048] The first cylinder chamber (41) is provided in a central portion of the first cylinder (40). The first suction passage (42) extends from the inner wall surface of the first cylinder chamber (41) toward the outside in the radial direction of the first cylinder (40). The first suction passage (42) is open to the outer surface of the first cylinder (40). One of the corresponding suction pipes (15) is connected to an inlet end of the first suction passage (42). An outlet end of the first suction passage (42) communicates with the first cylinder chamber (41).

[0049] The first cylinder chamber (41) houses the first roller (46) and a first vane (47). The first roller (46) is formed in an annular shape. The first roller (46) is fixed to the first eccentric portion (27) of the crankshaft (25). Specifically, the first eccentric portion (27) of the crankshaft (25) is fitted into the first roller (46).

[0050] The first vane (47) extends radially outward from the first roller (46). The first vane (47) is supported by a pair of first bushes (48). The inside of the first cylinder chamber (41) is divided by the first vane (47) into a low-pressure chamber and a high-pressure chamber.

[0051] The first roller (46) eccentrically rotates in the first cylinder chamber (41) as the crankshaft (25) is driven to rotate. When the volume of the low-pressure chamber gradually increases with the eccentric rotation of the first roller (46), the refrigerant flowing through the suction pipe (15) is sucked into the low-pressure chamber through the first suction passage (42).

[0052] When the low-pressure chamber is isolated from the first suction passage (42), the isolated space constitutes a high-pressure chamber. The internal pressure in the high-pressure chamber increases as the volume of the high-pressure chamber gradually decreases. When the internal pressure in the high-pressure chamber exceeds a predetermined pressure, the refrigerant in the high-pressure chamber flows out of the compression mechanism (30) through the first discharge passage (49). This high-pressure refrigerant flows upward in the internal space of the casing (13) and passes through core cuts (not shown) or other portions of the motor (21). The high-pressure refrigerant that has flowed into the secondary space (12) above the motor (21) is sent to the refrigerant circuit through the discharge pipe (16).

[0053] The first vane chamber (43) is provided radially outward of and away from the first cylinder chamber (41). The first vane chamber (43) extends through the first cylinder (40) in its thickness direction. The first vane chamber (43) houses a tip end portion of the first vane (47). The first vane (47) oscillates in the first vane chamber (43) as the first roller (46) rotates eccentrically.

[0054] As illustrated in FIG. 2, the middle plate (32) is sandwiched between the first cylinder (40) and the second cylinder (50). The middle plate (32) is disposed to cover the first cylinder chamber (41) of the first cylinder (40) from below. The middle plate (32) is disposed to cover the second cylinder chamber (51) of the second cylinder (50) from above.

[0055] As also illustrated in FIG. 4, the second cylinder (50) is configured as a flat and substantially annular member. The second cylinder (50) includes the second cylinder chamber (51), a second suction passage (52), and a second vane chamber (53).

[0056] The second cylinder chamber (51) is provided in a central portion of the second cylinder (50). The second suction passage (52) extends from the inner wall surface of the second cylinder chamber (51) toward the outside in the radial direction of the second cylinder (50). The second suction passage (52) is open to the outer surface of the second cylinder (50). The other suction pipe (15) is connected to an inlet end of the second suction passage (52). An outlet end of the second suction passage (52) communicates with the second cylinder chamber (51).

[0057] The second cylinder chamber (51) houses the second roller (56) and a second vane (57). The second roller (56) is formed in an annular shape. The second eccentric portion (28) of the crankshaft (25) is fitted into the second roller (56). The second vane (57) extends radially outward from the second roller (56). The second vane (57) is supported by a pair of second bushes (58). The inside of the second cylinder chamber (51) is divided by the second vane (57) into a low-pressure chamber and a high-pressure chamber.

[0058] The operation of the second roller (56) is substantially the same as that of the first roller (46), and thus, is not described below.

[0059] The second vane chamber (53) is provided radially outward of and away from the second cylinder chamber (51). The second vane chamber (53) extends through the second cylinder (50) in its thickness direction. The second vane chamber (53) houses a tip end portion of the second vane (57). The second vane (57) oscillates in the second vane chamber (53) as the second roller (56) rotates eccentrically.

[0060] As illustrated in FIG. 2, the rear head (33) is stacked on the bottom of the second cylinder (50). The rear head (33) is disposed to cover the second cylinder chamber (51) of the second cylinder (50) from below. The main shaft portion (26) of the crankshaft (25) is inserted through a central portion of the rear head (33). The rear head (33) rotatably supports the crankshaft (25). The rear head (33) has the second discharge passage (59) (see FIG. 4) extending therethrough in the axial direction. When the internal pressure in the high-pressure chamber of the second cylinder chamber (51) exceeds a predetermined pressure, the refrigerant in the high-pressure chamber flows out of the compression mechanism (30) through the second discharge passage (59).<Generation of Noise>

[0061] When spaces having different pressures, such as the primary space (11) and the secondary space (12), exist inside the casing (13), pressure fluctuations may be caused by space resonance, moving the crankshaft (25) in the axial direction, and as a result, the crankshaft (25) may collide with the front head (31), generating noise.

[0062] The inventors of the present application have found that when carbon dioxide is used as a refrigerant, the mass of the discharged refrigerant is larger than that of other refrigerants, and therefore, the excitation force that causes pressure fluctuations increases, making it more likely that noise is caused by the vertical vibration of the crankshaft (25).

[0063] In view of the above, in the present embodiment, consideration is given to reducing the collision of the crankshaft (25) with the front head (31), thereby reducing noise, when carbon dioxide is used as the refrigerant.

[0064] As shown in FIGS. 2 and 5, the distance between the upper end of the secondary space (12) and the suction port (39) of the oil supply mechanism (38) is denoted by L0 [mm]. The distance between the first discharge port (63) and a midpoint (L0 / 2) between the upper end of the secondary space (12) and the suction port (39) of the oil supply mechanism (38), is denoted by L [mm].

[0065] As shown in FIG. 2, the distance between the lower end of a member joined to the casing (13), among the members constituting the compression mechanism (30), and the suction port (39) of the oil supply mechanism (38) is denoted by L1 [mm]. In the example shown in FIG. 2, the member joined to the casing (13) among the members constituting the compression mechanism (30) is the front head (31), which is joined via the mounting plate (36). The distance between the first discharge port (63) and the lower end of the front head (31) is denoted by L2 [mm]. In this case, L0 / 2 = L + L1 + L2.

[0066] The displacement volume per rotation of the compression mechanism (30) is denoted by Vcc [cc]. Here, the displacement volume Vcc is the volume of the compression chamber at the time of full closure of the first cylinder (40), that is, at the time when the low-pressure chamber is sealed in the first cylinder chamber (41) to form the compression chamber.

[0067] The present embodiment deals with a case where the displacement volumes Vcc of the first cylinder (40) and the second cylinder (50) are the same. However, when the displacement volumes Vcc of the first cylinder chamber (41) and the second cylinder chamber (51) are different from each other, for example, the following consideration is made for the cylinder having the larger Vcc.

[0068] In the following description, the number of revolutions of the rotor (23) that is equal to or higher than a predetermined number of revolutions is referred to as a maximum number of revolutions. The predetermined number of revolutions is 100 rps or higher. The maximum number of revolutions of the rotor (23) is between 110 rps and 130 rps, inclusive, and is, for example, 120 rps.

[0069] In FIG. 2, the first discharge port (63) serves as the excitation position of the resonance. In the present embodiment, the first muffler (61) and the second muffler (65) are provided; and since the first muffler (61) is disposed outside the second muffler (65), the first discharge port (63) of the first muffler (61) serves as the excitation position of the resonance. In the case where the first muffler (61) and the second muffler (65) are not provided, a discharge port of the first discharge passage (49) of the front head (31) functions as the first discharge port (63) serving as the excitation position of the resonance.

[0070] FIG. 5 is a diagram showing a waveform of pressure fluctuations caused by space resonance. In the present embodiment, the resonance frequency is, for example, 180 Hz. In the example shown in FIG. 5, the excitation position of the resonance is shifted by sin(πL / L0) from the position of the node of the resonance. The closer the first discharge port (63), serving as the excitation position of the resonance, is to the node of the resonance, the less likely the resonance is to be excited.

[0071] Thus, in the present embodiment, the distance L1 is increased to bring the excitation position of the resonance closer to the node. Furthermore, the smaller the displacement volume Vcc is, the smaller the discharge amount of the refrigerant becomes and the smaller the excitation force of the resonance becomes. Focusing on this point, a parameter L1 / Vcc is set.

[0072] In the graph of FIG. 6, where the horizontal axis is denoted as x and the vertical axis is denoted as y, the plots indicating the distances L1 of known refrigerant compressors used as comparative examples are located below the straight line defined by y = 11.4x.

[0073] In contrast, the plots indicating the distances L1 of the refrigerant compressors (10) according to the present embodiment are located above the straight line defined by y = 13.2x. In the example shown in FIG. 6, the plots indicating the distances L1 are located above the straight line defined by y = 13.5x, except for the one corresponding to Vcc = 11.0.

[0074] In view of the above, in the present embodiment, the parameter L1 / Vcc is set so as to satisfy the following expression (1). L 1 / Vcc > 13

[0075] Thus, the distance L decreases by increasing the distance L1 so as to satisfy the expression (1). That is, the position of the first discharge port (63), which serves as the excitation position of the resonance, can be brought closer to the node. This can reduce the collision of the crankshaft (25) with the front head (31) and thus can reduce noise.

[0076] The total weight of the rotor (23) and the crankshaft (25) is denoted by M [kg]. The total weight M includes the weight of components that are attached to the rotor (23) and the crankshaft (25) and rotate together with the rotor (23) and the crankshaft (25). For example, when a balance weight, an end plate member, or the like is attached to the rotor (23), the total weight M includes the weight of such components.

[0077] As the total weight M increases, the crankshaft (25) becomes less likely to move vertically. Focusing on this point, a parameter Vcc × sin(πL / L0) / M is set in the present embodiment.

[0078] In the graph of FIG. 7, where the horizontal axis denoted as x and the vertical axis denoted as y, the plots indicating the parameters Vcc × sin(πL / L0) of known refrigerant compressors used as comparative examples are located above the straight line defined by y = 1.09x.

[0079] In contrast, the plots indicating the parameters Vcc × sin(πL / L0) of the refrigerant compressors (10) according to the present embodiment are located below the straight line defined by y = 0.90x.

[0080] In view of the above, in the present embodiment, the parameter Vcc × sin(πL / L0) / M is set so as to satisfy the following expression (2). Vcc × sin πL / L 0 / M ≤ 0.90

[0081] In the example shown in FIG. 7, a plot indicating the parameter Vcc × sin(πL / L0) at around M = 2.8 substantially lies on the straight line defined by y = 0.86x, and the other plots representing the present embodiment are located below the straight line defined by y = 0.86x.

[0082] In view of the above, in the present embodiment, the parameter Vcc × sin(πL / L0) / M is set so as to further satisfy the following expression (3). Vcc × sin πL / L 0 / M ≤ 0.86

[0083] As described above, the greater the total weight M of the rotor (23) and the crankshaft (25) is, the less likely the crankshaft (25) is to move vertically. Furthermore, the greater the parameter L1 / Vcc in the above expression (1) is, the smaller the parameter Vcc × sin(πL / L0) becomes.

[0084] FIG. 8 is a graph showing the relationship between the number of revolutions of the rotor and the differential pressure load. The differential pressure load is a value obtained by multiplying the maximum value of the differential pressure between the primary space (11) and the secondary space (12) by the pressure receiving area of the rotor (23). The smaller the differential pressure load, the less likely noise is to be caused by the collision of the crankshaft (25) with the front head (31).

[0085] As shown in FIG. 8, the differential pressure loads of the refrigerant compressor (10) of the present embodiment with the parameter Vcc × sin(πL / L0) / M set to 0.90 or 0.86 are smaller than those of the refrigerant compressor of the comparative example with the parameter Vcc × sin(πL / L0) / M set to 1.09. Furthermore, the peak differential pressure load values of the refrigerant compressor (10) of the present embodiment are smaller than the peak differential pressure load value of the refrigerant compressor of the comparative example.

[0086] Thus, in the present embodiment, the differential pressure load, which corresponds to the maximum value of the differential pressure between the primary space (11) and the secondary space (12), can be reduced, thereby reducing noise caused by the collision of the crankshaft (25) with the front head (31).- Advantages of Embodiment -

[0087] According to the present embodiment, by increasing the distance L1 so as to satisfy the condition of the expression (1) described above and thereby bringing the excitation position of the resonance closer to the node, pressure fluctuations caused by the resonance are decreased, which can reduce the collision of the crankshaft (25) with the first head (31), thereby reducing noise.

[0088] According to the present embodiment, by satisfying the condition of the expression (2) described above, pressure fluctuations caused by the resonance can be decreased, thereby reducing noise caused by the collision of the crankshaft (25) with the first head (31).

[0089] Specifically, the smaller the displacement volume Vcc is, the smaller the discharge amount of the refrigerant becomes and the smaller the excitation force of the resonance becomes. The closer the discharge port (63), serving as the excitation position of the resonance, is to the node of the resonance, the less likely the resonance is to be excited. The greater the total weight M of the rotor (23) and the crankshaft (25) is, the less likely the crankshaft (25) is to move vertically. The greater the parameter L1 / Vcc becomes, the smaller the parameter Vcc × sin(πL / L0) becomes.

[0090] According to the present embodiment, it is possible to further reduce the vertical movement of the crankshaft (25) caused by pressure fluctuations due to the resonance, thereby reducing noise generation.

[0091] According to the present embodiment, satisfying the above-described conditions can help reduce pressure fluctuations caused by the resonance, thereby reducing noise generation, even in a large-volume, multi-cylinder refrigerant compressor including the first cylinder (40) and the first roller (46), and the second cylinder (50) and the second roller (56), which tends to generate noise easily.

[0092] According to the present embodiment, the maximum number of revolutions of the rotor (23) is set to 100 rps or higher, which lowers the oil level and the resonance frequency. Therefore, even if the rotor (23) is rotated at a high speed and a collision with the resonance occurs, noise generation can be reduced.

[0093] According to the present embodiment, a refrigeration apparatus including the refrigerant compressor (10) can be provided.

[0094] According to the present embodiment, an air-conditioning system including the refrigeration apparatus (1) serving as an air-conditioning apparatus can be provided.<<Other Embodiments>>

[0095] While the embodiments and variations have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the claims. The elements according to the embodiments, the variations thereof, and the other embodiments may be combined and replaced with each other. In addition, the expressions of "first," "second," "third," . . . , in the specification and claims are used to distinguish the terms to which these expressions are given, and do not limit the number and order of the terms.INDUSTRIAL APPLICABILITY

[0096] As described above, the present disclosure is useful for a refrigerant compressor, a refrigeration apparatus, and an air-conditioning system.DESCRIPTION OF REFERENCE CHARACTERS

[0097] 1Refrigeration Apparatus 10Refrigerant Compressor 11Primary Space 12Secondary Space 13Casing 21Motor 23Rotor 25Crankshaft 27First Eccentric Portion (Eccentric Portion) 30Compression Mechanism 31Front Head (First Head) 38Oil Supply Mechanism 39Suction Port 40First Cylinder 41First Cylinder Chamber 46First Roller 50Second Cylinder 51Second Cylinder Chamber 56Second Roller 63First Discharge Port (Discharge Port) 70Cylinder 71Cylinder Chamber 76Roller 100Air-Conditioning System

Examples

embodiment -

- Advantages of Embodiment -

[0087]According to the present embodiment, by increasing the distance L1 so as to satisfy the condition of the expression (1) described above and thereby bringing the excitation position of the resonance closer to the node, pressure fluctuations caused by the resonance are decreased, which can reduce the collision of the crankshaft (25) with the first head (31), thereby reducing noise.

[0088]According to the present embodiment, by satisfying the condition of the expression (2) described above, pressure fluctuations caused by the resonance can be decreased, thereby reducing noise caused by the collision of the crankshaft (25) with the first head (31).

[0089]Specifically, the smaller the displacement volume Vcc is, the smaller the discharge amount of the refrigerant becomes and the smaller the excitation force of the resonance becomes. The closer the discharge port (63), serving as the excitation position of the resonance, is to the node of the resonance, the...

TECHNICAL FIELD

[0001] The present disclosure relates to a refrigerant compressor, a refrigeration apparatus, and an air-conditioning system.BACKGROUND ART

[0002] Patent Document 1 discloses that when spaces having different pressures, such as a primary space and a secondary space, exist inside a casing of a rotary compressor, pressure fluctuations may be caused by space resonance, moving a crankshaft in an axial direction, and as a result, the crankshaft may collide with a head, generating noise.

[0003] In Patent Document 1, the dimensions of the components of the rotary compressor are designed, or its operation is adjusted, so that the operation frequency is (resonance frequency / 1.2) or less, thereby reducing noise generated by the vertical vibration of the crankshaft.CITATION LISTPATENT DOCUMENT

[0004] [PATENT DOCUMENT 1] Japanese Unexamined Patent Publication No. H10-089252SUMMARY OF THE INVENTIONTECHNICAL PROBLEM

[0005] The inventors of the present application have found that when carbon dioxide is used as a refrigerant, the mass of the discharged refrigerant is larger than that of other refrigerants, and therefore, the excitation force that causes pressure fluctuations increases, making it more likely that noise is caused by the vertical vibration of the crankshaft.

[0006] An object of the present disclosure is to reduce the collision of a crankshaft with a head, thereby reducing noise, when carbon dioxide is used as a refrigerant.SOLUTION TO THE PROBLEM

[0007] A first aspect of the present disclosure is directed to a refrigerant compressor using carbon dioxide as a refrigerant, the refrigerant compressor including: a crankshaft (25) extending along a first direction and having an eccentric portion (27); a motor (21) configured to rotate the crankshaft (25); a compression mechanism (30) coupled to the crankshaft (25) and configured to be driven by the crankshaft (25); and a casing (13) which houses the crankshaft (25), the motor (21), and the compression mechanism (30), and in which a primary space (11) below the motor (21) and a secondary space (12) above the motor (21) are formed, the compression mechanism (30) including: a first head (31) rotatably supporting the crankshaft (25); a cylinder (70) disposed adjacent to the first head (31) and including a cylinder chamber (71); and a roller (76) fixed to the eccentric portion (27) and configured to eccentrically rotate in the cylinder chamber (71), the eccentric portion (27) having an upper surface overlapping with a part of a lower surface of the first head (31) when viewed from the first direction, the crankshaft (25) being provided with, at a lower end portion thereof, an oil supply mechanism (38) including a suction port (39) through which oil stored in a lower end portion of the casing (13) is drawn, a displacement volume Vcc [cc] per rotation of the compression mechanism (30) and a distance L1 [mm] between the suction port (39) and a lower end of a member joined to the casing (13), among members constituting the compression mechanism (30), satisfying the following condition: L1 / Vcc > 13.

[0008] According to the first aspect, by increasing the distance L1 so as to satisfy the condition described above and thereby bringing the excitation position of the resonance closer to the node, pressure fluctuations caused by the resonance are decreased, which can reduce the collision of the crankshaft (25) with the first head (31), thereby reducing noise.

[0009] A second aspect of the present disclosure is an embodiment of the refrigerant compressor of the first aspect. In the second aspect, the compression mechanism (30) is provided with a discharge port (63) through which compressed refrigerant is discharged to the primary space (11), and a distance L0 [mm] between an upper end of the secondary space (12) and the suction port (39), a distance L [mm] between the discharge port (63) and a midpoint between the upper end of the secondary space (12) and the suction port (39), and a total weight M [kg] of a rotor (23) of the motor (21) and the crankshaft (25) satisfy the following condition: Vcc × sin πL / L 0 / M ≤ 0.90 .

[0010] According to the second aspect, by satisfying the condition described above, pressure fluctuations caused by the resonance can be decreased, thereby reducing noise caused by the collision of the crankshaft (25) with the first head (31).

[0011] Specifically, the smaller the displacement volume Vcc is, the smaller the discharge amount of the refrigerant becomes and the smaller the excitation force of the resonance becomes. The closer the discharge port (63), serving as the excitation position of the resonance, is to the node of the resonance, the less likely the resonance is to be excited. The greater the total weight M of the rotor (23) and the crankshaft (25) is, the less likely the crankshaft (25) is to move vertically. The greater the parameter L1 / Vcc becomes, the smaller the parameter Vcc × sin(πL / L0) becomes.

[0012] A third aspect of the present disclosure is an embodiment of the refrigerant compressor of the second aspect. In the third aspect, the following condition is satisfied: Vcc × sin(πL / L0) / M ≤ 0.86.

[0013] According to the third aspect, it is possible to further reduce the vertical movement of the crankshaft (25) caused by pressure fluctuations due to the resonance, thereby reducing noise generation.

[0014] A fourth aspect of the present disclosure is an embodiment of the refrigerant compressor of any one of the first to third aspects. In the fourth aspect, the cylinder (70) includes: a first cylinder (40) including a first cylinder chamber (41); and a second cylinder (50) including a second cylinder chamber (51), and the roller (76) includes: a first roller (46) housed in the first cylinder chamber (41); and a second roller (56) housed in the second cylinder chamber (51).

[0015] According to the fourth aspect, satisfying the above-described conditions can help reduce pressure fluctuations caused by the resonance, thereby reducing noise generation, even in a large-volume, multi-cylinder refrigerant compressor including the first cylinder (40) and the first roller (46), and the second cylinder (50) and the second roller (56), which tends to generate noise easily.

[0016] A fifth aspect of the present disclosure is an embodiment of the refrigerant compressor of any one of the first to fourth aspects. In the fifth aspect, a maximum number of revolutions of a rotor (23) of the motor (21) is 100 rps or higher.

[0017] According to the fifth aspect, the maximum number of revolutions of the rotor (23) is set to 100 rps or higher, which lowers the oil level and the resonance frequency. Therefore, even if the rotor (23) is rotated at a high speed and a collision with the resonance occurs, noise generation can be reduced.

[0018] A sixth aspect of the present disclosure is directed to a refrigeration apparatus including the refrigerant compressor (10) of any one of the first to fifth aspects.

[0019] According to the sixth aspect, a refrigeration apparatus including the refrigerant compressor (10) can be provided.

[0020] A seventh aspect of the present disclosure is directed to an air-conditioning system including the refrigeration apparatus (1) of the sixth aspect, the refrigeration apparatus (1) being an air-conditioning apparatus configured to condition air in a predetermined target space.

[0021] According to the seventh aspect, an air-conditioning system including the refrigeration apparatus (1) serving as an air-conditioning apparatus can be provided.BRIEF DESCRIPTION OF THE DRAWINGS

[0022] [FIG. 1] FIG. 1 is a refrigerant circuit diagram illustrating a configuration of an air-conditioning system of an embodiment. [FIG. 2] FIG. 2 is a vertical sectional view illustrating a configuration of a refrigerant compressor. [FIG. 3] FIG. 3 is a transverse sectional view illustrating a configuration of a first cylinder and a first roller. [FIG. 4] FIG. 4 is a transverse sectional view illustrating a configuration of a second cylinder and a second roller. [FIG. 5] FIG. 5 is a diagram showing a waveform of pressure fluctuations caused by space resonance. [FIG. 6] FIG. 6 is a graph showing the relationship between the displacement volume Vcc and the distance L1. [FIG. 7] FIG. 7 is a graph showing the relationship between the total weight M and the parameter Vcc × sin(πL / L0). [FIG. 8] FIG. 8 is a graph showing the relationship between the number of revolutions of a rotor and the differential pressure load. DESCRIPTION OF EMBODIMENTS

[0023] As shown in FIG. 1, an air-conditioning system (100) includes a refrigeration apparatus (1) serving as an air-conditioning apparatus that conditions air in a predetermined target space. The refrigeration apparatus (1) includes a refrigerant circuit (1a) filled with a refrigerant. In the present embodiment, carbon dioxide is used as the refrigerant.

[0024] The refrigerant circuit (1a) includes a refrigerant compressor (10), a radiator (3), a decompression mechanism (4), and an evaporator (5). The decompression mechanism (4) is, for example, an expansion valve. The refrigerant circuit (1a) performs a vapor compression refrigeration cycle.

[0025] The refrigeration apparatus (1) may be any of a cooling-only apparatus, a heating-only apparatus, or an air-conditioning apparatus switchable between cooling and heating. In this case, the refrigeration apparatus (1) has a switching mechanism (e.g., a four-way switching valve) for switching the directions of circulation of the refrigerant.

[0026] As shown in FIG. 2, the refrigerant compressor (10) includes a casing (13), a drive mechanism (20), and a compression mechanism (30). The drive mechanism (20) and the compression mechanism (30) are housed in the casing (13).

[0027] The casing (13) is configured as a vertically long cylindrical closed container. An oil reservoir (18) is provided at the bottom of the casing (13). The oil reservoir (18) stores oil for lubricating sliding portions of the compression mechanism (30) and a crankshaft (25).

[0028] Suction pipes (15) and a discharge pipe (16) are inserted through and fixed to a barrel of the casing (13). An accumulator (80) is connected to the suction pipes (15). The accumulator (80) temporarily stores the refrigerant to be sucked into the refrigerant compressor (10) and performs gas-liquid separation for the liquid refrigerant and oil contained in the gas refrigerant. The discharge pipe (16) communicates with a secondary space (12) of the casing (13), which will be described later.<Drive Mechanism>

[0029] The drive mechanism (20) includes a motor (21) and the crankshaft (25). The motor (21) is disposed above the compression mechanism (30). The motor (21) includes a stator (22) and a rotor (23).

[0030] The stator (22) is fixed to the inner peripheral surface of the casing (13). The rotor (23) extends vertically through the interior of the stator (22). The crankshaft (25) is fixed inside the axial center of the rotor (23). The crankshaft (25) is driven to rotate together with the rotor (23) when the motor (21) is energized.

[0031] A primary space (11) and the secondary space (12) are formed inside the casing (13). The primary space (11) is a space below the motor (21). The secondary space (12) is a space above the motor (21).

[0032] The crankshaft (25) is arranged on the axis of the casing (13). The crankshaft (25) extends along a first direction (the vertical direction in FIG. 2). An oil supply mechanism (38) is provided at a lower end portion of the crankshaft (25). The oil supply mechanism (38) has a suction port (39). The oil supply mechanism (38) draws oil stored in the oil reservoir (18) through the suction port (39) and conveys the oil. The conveyed oil is supplied to the sliding portions of the compression mechanism (30) and the crankshaft (25) through an oil passage (29) inside the crankshaft (25).

[0033] Although the crankshaft (25) and the oil supply mechanism (38) are separate components in the present embodiment, the crankshaft (25) and the oil supply mechanism (38) may be integrated with each other.

[0034] The crankshaft (25) includes a main shaft portion (26), a first eccentric portion (27), and a second eccentric portion (28). An upper portion of the main shaft portion (26) is fixed to the rotor (23) of the motor (21). The first eccentric portion (27) is located above the second eccentric portion (28). The axes of the first eccentric portion (27) and the second eccentric portion (28) are eccentric from the axis of the main shaft portion (26) by a predetermined amount.

[0035] Part of the main shaft portion (26) above the first eccentric portion (27) is rotatably supported by a front head (31) described later. Part of the main shaft portion (26) below the second eccentric portion (28) is rotatably supported by a rear head (33) described later.<Compression Mechanism>

[0036] In the example shown in FIG. 2, the compression mechanism (30) is a two-cylinder rotary fluid machine. The compression mechanism (30) is disposed below the motor (21). The compression mechanism (30) is coupled to and driven by the crankshaft (25).

[0037] The refrigerant compressor of the present embodiment is of a type in which each roller eccentrically rotates with a vane connected to a specific position of an outer peripheral portion of the roller. The refrigerant compressor may be a so-called swing compressor in which a vane and a roller are integrally formed, or may be a hinged-vane compressor in which a vane, as a separate component from a roller, is rotatably fixed to an end portion of the roller. The following will describe the compression mechanism (30) in which each vane and the corresponding roller are integrally formed.

[0038] The compression mechanism (30) includes a cylinder (70) having a cylinder chamber (71). The cylinder chamber (71) houses a roller (76). The cylinder chamber (71) includes a first cylinder chamber (41) and a second cylinder chamber (51). The cylinder (70) includes a first cylinder (40) having the first cylinder chamber (41) and a second cylinder (50) having the second cylinder chamber (51). The roller (76) includes a first roller (46) housed in the first cylinder chamber (41) and a second roller (56) housed in the second cylinder chamber (51).

[0039] The compression mechanism (30) includes the front head (31) as a first head, the first cylinder (40), a middle plate (32), the second cylinder (50), and the rear head (33).

[0040] The front head (31), the first cylinder (40), the middle plate (32), the second cylinder (50), and the rear head (33) are stacked in this order from top to bottom and fixed with a fastening bolt (35).

[0041] The front head (31) is fixed to the casing (13) via a mounting plate (36). The front head (31) may be joined to the casing (13) without using the mounting plate (36). Furthermore, instead of the front head (31), any of the first cylinder (40), the second cylinder (50), and the rear head (33) may be joined to the casing (13).

[0042] The front head (31) is stacked on top of the first cylinder (40). The front head (31) is arranged to cover the first cylinder chamber (41) of the first cylinder (40) from above.

[0043] The main shaft portion (26) of the crankshaft (25) is inserted through a central portion of the front head (31). The front head (31) rotatably supports the crankshaft (25). The front head (31) has a first discharge passage (49) (see FIG. 3) extending therethrough in the axial direction. The upper surface of the first eccentric portion (27) overlaps with a part of the lower surface of the front head (31) when viewed from the first direction (i.e., the axial direction of the crankshaft (25)).

[0044] A first muffler (61) and a second muffler (65) are provided on an upper surface of the front head (31). The first muffler (61) covers the first discharge passage (49) (see FIG. 3) so as to define a first muffler space (62). The second muffler (65) is disposed in the first muffler space (62). The second muffler (65) defines a second muffler space (66) between itself and the front head (31). A second discharge passage (59) (see FIG. 4) communicates with the second muffler space (66).

[0045] The first muffler (61) has a first discharge port (63). The first discharge port (63) communicates with the first muffler space (62) and the primary space (11). The compressed refrigerant discharged from the first discharge passage (49) is discharged to the primary space (11) through the first discharge port (63).

[0046] The second muffler (65) has a second discharge port (67). The second discharge port (67) communicates with the second muffler space (66) and the first muffler space (62). The compressed refrigerant discharged from the second discharge passage (59) is discharged to the first muffler space (62) through the second discharge port (67).

[0047] The first cylinder (40) is configured as a flat and substantially annular member. The first cylinder (40) is disposed adjacent to the front head (31). As shown in FIG. 3, the first cylinder (40) includes the first cylinder chamber (41), a first suction passage (42), and a first vane chamber (43).

[0048] The first cylinder chamber (41) is provided in a central portion of the first cylinder (40). The first suction passage (42) extends from the inner wall surface of the first cylinder chamber (41) toward the outside in the radial direction of the first cylinder (40). The first suction passage (42) is open to the outer surface of the first cylinder (40). One of the corresponding suction pipes (15) is connected to an inlet end of the first suction passage (42). An outlet end of the first suction passage (42) communicates with the first cylinder chamber (41).

[0049] The first cylinder chamber (41) houses the first roller (46) and a first vane (47). The first roller (46) is formed in an annular shape. The first roller (46) is fixed to the first eccentric portion (27) of the crankshaft (25). Specifically, the first eccentric portion (27) of the crankshaft (25) is fitted into the first roller (46).

[0050] The first vane (47) extends radially outward from the first roller (46). The first vane (47) is supported by a pair of first bushes (48). The inside of the first cylinder chamber (41) is divided by the first vane (47) into a low-pressure chamber and a high-pressure chamber.

[0051] The first roller (46) eccentrically rotates in the first cylinder chamber (41) as the crankshaft (25) is driven to rotate. When the volume of the low-pressure chamber gradually increases with the eccentric rotation of the first roller (46), the refrigerant flowing through the suction pipe (15) is sucked into the low-pressure chamber through the first suction passage (42).

[0052] When the low-pressure chamber is isolated from the first suction passage (42), the isolated space constitutes a high-pressure chamber. The internal pressure in the high-pressure chamber increases as the volume of the high-pressure chamber gradually decreases. When the internal pressure in the high-pressure chamber exceeds a predetermined pressure, the refrigerant in the high-pressure chamber flows out of the compression mechanism (30) through the first discharge passage (49). This high-pressure refrigerant flows upward in the internal space of the casing (13) and passes through core cuts (not shown) or other portions of the motor (21). The high-pressure refrigerant that has flowed into the secondary space (12) above the motor (21) is sent to the refrigerant circuit through the discharge pipe (16).

[0053] The first vane chamber (43) is provided radially outward of and away from the first cylinder chamber (41). The first vane chamber (43) extends through the first cylinder (40) in its thickness direction. The first vane chamber (43) houses a tip end portion of the first vane (47). The first vane (47) oscillates in the first vane chamber (43) as the first roller (46) rotates eccentrically.

[0054] As illustrated in FIG. 2, the middle plate (32) is sandwiched between the first cylinder (40) and the second cylinder (50). The middle plate (32) is disposed to cover the first cylinder chamber (41) of the first cylinder (40) from below. The middle plate (32) is disposed to cover the second cylinder chamber (51) of the second cylinder (50) from above.

[0055] As also illustrated in FIG. 4, the second cylinder (50) is configured as a flat and substantially annular member. The second cylinder (50) includes the second cylinder chamber (51), a second suction passage (52), and a second vane chamber (53).

[0056] The second cylinder chamber (51) is provided in a central portion of the second cylinder (50). The second suction passage (52) extends from the inner wall surface of the second cylinder chamber (51) toward the outside in the radial direction of the second cylinder (50). The second suction passage (52) is open to the outer surface of the second cylinder (50). The other suction pipe (15) is connected to an inlet end of the second suction passage (52). An outlet end of the second suction passage (52) communicates with the second cylinder chamber (51).

[0057] The second cylinder chamber (51) houses the second roller (56) and a second vane (57). The second roller (56) is formed in an annular shape. The second eccentric portion (28) of the crankshaft (25) is fitted into the second roller (56). The second vane (57) extends radially outward from the second roller (56). The second vane (57) is supported by a pair of second bushes (58). The inside of the second cylinder chamber (51) is divided by the second vane (57) into a low-pressure chamber and a high-pressure chamber.

[0058] The operation of the second roller (56) is substantially the same as that of the first roller (46), and thus, is not described below.

[0059] The second vane chamber (53) is provided radially outward of and away from the second cylinder chamber (51). The second vane chamber (53) extends through the second cylinder (50) in its thickness direction. The second vane chamber (53) houses a tip end portion of the second vane (57). The second vane (57) oscillates in the second vane chamber (53) as the second roller (56) rotates eccentrically.

[0060] As illustrated in FIG. 2, the rear head (33) is stacked on the bottom of the second cylinder (50). The rear head (33) is disposed to cover the second cylinder chamber (51) of the second cylinder (50) from below. The main shaft portion (26) of the crankshaft (25) is inserted through a central portion of the rear head (33). The rear head (33) rotatably supports the crankshaft (25). The rear head (33) has the second discharge passage (59) (see FIG. 4) extending therethrough in the axial direction. When the internal pressure in the high-pressure chamber of the second cylinder chamber (51) exceeds a predetermined pressure, the refrigerant in the high-pressure chamber flows out of the compression mechanism (30) through the second discharge passage (59).<Generation of Noise>

[0061] When spaces having different pressures, such as the primary space (11) and the secondary space (12), exist inside the casing (13), pressure fluctuations may be caused by space resonance, moving the crankshaft (25) in the axial direction, and as a result, the crankshaft (25) may collide with the front head (31), generating noise.

[0062] The inventors of the present application have found that when carbon dioxide is used as a refrigerant, the mass of the discharged refrigerant is larger than that of other refrigerants, and therefore, the excitation force that causes pressure fluctuations increases, making it more likely that noise is caused by the vertical vibration of the crankshaft (25).

[0063] In view of the above, in the present embodiment, consideration is given to reducing the collision of the crankshaft (25) with the front head (31), thereby reducing noise, when carbon dioxide is used as the refrigerant.

[0064] As shown in FIGS. 2 and 5, the distance between the upper end of the secondary space (12) and the suction port (39) of the oil supply mechanism (38) is denoted by L0 [mm]. The distance between the first discharge port (63) and a midpoint (L0 / 2) between the upper end of the secondary space (12) and the suction port (39) of the oil supply mechanism (38), is denoted by L [mm].

[0065] As shown in FIG. 2, the distance between the lower end of a member joined to the casing (13), among the members constituting the compression mechanism (30), and the suction port (39) of the oil supply mechanism (38) is denoted by L1 [mm]. In the example shown in FIG. 2, the member joined to the casing (13) among the members constituting the compression mechanism (30) is the front head (31), which is joined via the mounting plate (36). The distance between the first discharge port (63) and the lower end of the front head (31) is denoted by L2 [mm]. In this case, L0 / 2 = L + L1 + L2.

[0066] The displacement volume per rotation of the compression mechanism (30) is denoted by Vcc [cc]. Here, the displacement volume Vcc is the volume of the compression chamber at the time of full closure of the first cylinder (40), that is, at the time when the low-pressure chamber is sealed in the first cylinder chamber (41) to form the compression chamber.

[0067] The present embodiment deals with a case where the displacement volumes Vcc of the first cylinder (40) and the second cylinder (50) are the same. However, when the displacement volumes Vcc of the first cylinder chamber (41) and the second cylinder chamber (51) are different from each other, for example, the following consideration is made for the cylinder having the larger Vcc.

[0068] In the following description, the number of revolutions of the rotor (23) that is equal to or higher than a predetermined number of revolutions is referred to as a maximum number of revolutions. The predetermined number of revolutions is 100 rps or higher. The maximum number of revolutions of the rotor (23) is between 110 rps and 130 rps, inclusive, and is, for example, 120 rps.

[0069] In FIG. 2, the first discharge port (63) serves as the excitation position of the resonance. In the present embodiment, the first muffler (61) and the second muffler (65) are provided; and since the first muffler (61) is disposed outside the second muffler (65), the first discharge port (63) of the first muffler (61) serves as the excitation position of the resonance. In the case where the first muffler (61) and the second muffler (65) are not provided, a discharge port of the first discharge passage (49) of the front head (31) functions as the first discharge port (63) serving as the excitation position of the resonance.

[0070] FIG. 5 is a diagram showing a waveform of pressure fluctuations caused by space resonance. In the present embodiment, the resonance frequency is, for example, 180 Hz. In the example shown in FIG. 5, the excitation position of the resonance is shifted by sin(πL / L0) from the position of the node of the resonance. The closer the first discharge port (63), serving as the excitation position of the resonance, is to the node of the resonance, the less likely the resonance is to be excited.

[0071] Thus, in the present embodiment, the distance L1 is increased to bring the excitation position of the resonance closer to the node. Furthermore, the smaller the displacement volume Vcc is, the smaller the discharge amount of the refrigerant becomes and the smaller the excitation force of the resonance becomes. Focusing on this point, a parameter L1 / Vcc is set.

[0072] In the graph of FIG. 6, where the horizontal axis is denoted as x and the vertical axis is denoted as y, the plots indicating the distances L1 of known refrigerant compressors used as comparative examples are located below the straight line defined by y = 11.4x.

[0073] In contrast, the plots indicating the distances L1 of the refrigerant compressors (10) according to the present embodiment are located above the straight line defined by y = 13.2x. In the example shown in FIG. 6, the plots indicating the distances L1 are located above the straight line defined by y = 13.5x, except for the one corresponding to Vcc = 11.0.

[0074] In view of the above, in the present embodiment, the parameter L1 / Vcc is set so as to satisfy the following expression (1). L 1 / Vcc > 13

[0075] Thus, the distance L decreases by increasing the distance L1 so as to satisfy the expression (1). That is, the position of the first discharge port (63), which serves as the excitation position of the resonance, can be brought closer to the node. This can reduce the collision of the crankshaft (25) with the front head (31) and thus can reduce noise.

[0076] The total weight of the rotor (23) and the crankshaft (25) is denoted by M [kg]. The total weight M includes the weight of components that are attached to the rotor (23) and the crankshaft (25) and rotate together with the rotor (23) and the crankshaft (25). For example, when a balance weight, an end plate member, or the like is attached to the rotor (23), the total weight M includes the weight of such components.

[0077] As the total weight M increases, the crankshaft (25) becomes less likely to move vertically. Focusing on this point, a parameter Vcc × sin(πL / L0) / M is set in the present embodiment.

[0078] In the graph of FIG. 7, where the horizontal axis denoted as x and the vertical axis denoted as y, the plots indicating the parameters Vcc × sin(πL / L0) of known refrigerant compressors used as comparative examples are located above the straight line defined by y = 1.09x.

[0079] In contrast, the plots indicating the parameters Vcc × sin(πL / L0) of the refrigerant compressors (10) according to the present embodiment are located below the straight line defined by y = 0.90x.

[0080] In view of the above, in the present embodiment, the parameter Vcc × sin(πL / L0) / M is set so as to satisfy the following expression (2). Vcc × sin πL / L 0 / M ≤ 0.90

[0081] In the example shown in FIG. 7, a plot indicating the parameter Vcc × sin(πL / L0) at around M = 2.8 substantially lies on the straight line defined by y = 0.86x, and the other plots representing the present embodiment are located below the straight line defined by y = 0.86x.

[0082] In view of the above, in the present embodiment, the parameter Vcc × sin(πL / L0) / M is set so as to further satisfy the following expression (3). Vcc × sin πL / L 0 / M ≤ 0.86

[0083] As described above, the greater the total weight M of the rotor (23) and the crankshaft (25) is, the less likely the crankshaft (25) is to move vertically. Furthermore, the greater the parameter L1 / Vcc in the above expression (1) is, the smaller the parameter Vcc × sin(πL / L0) becomes.

[0084] FIG. 8 is a graph showing the relationship between the number of revolutions of the rotor and the differential pressure load. The differential pressure load is a value obtained by multiplying the maximum value of the differential pressure between the primary space (11) and the secondary space (12) by the pressure receiving area of the rotor (23). The smaller the differential pressure load, the less likely noise is to be caused by the collision of the crankshaft (25) with the front head (31).

[0085] As shown in FIG. 8, the differential pressure loads of the refrigerant compressor (10) of the present embodiment with the parameter Vcc × sin(πL / L0) / M set to 0.90 or 0.86 are smaller than those of the refrigerant compressor of the comparative example with the parameter Vcc × sin(πL / L0) / M set to 1.09. Furthermore, the peak differential pressure load values of the refrigerant compressor (10) of the present embodiment are smaller than the peak differential pressure load value of the refrigerant compressor of the comparative example.

[0086] Thus, in the present embodiment, the differential pressure load, which corresponds to the maximum value of the differential pressure between the primary space (11) and the secondary space (12), can be reduced, thereby reducing noise caused by the collision of the crankshaft (25) with the front head (31).- Advantages of Embodiment -

[0087] According to the present embodiment, by increasing the distance L1 so as to satisfy the condition of the expression (1) described above and thereby bringing the excitation position of the resonance closer to the node, pressure fluctuations caused by the resonance are decreased, which can reduce the collision of the crankshaft (25) with the first head (31), thereby reducing noise.

[0088] According to the present embodiment, by satisfying the condition of the expression (2) described above, pressure fluctuations caused by the resonance can be decreased, thereby reducing noise caused by the collision of the crankshaft (25) with the first head (31).

[0089] Specifically, the smaller the displacement volume Vcc is, the smaller the discharge amount of the refrigerant becomes and the smaller the excitation force of the resonance becomes. The closer the discharge port (63), serving as the excitation position of the resonance, is to the node of the resonance, the less likely the resonance is to be excited. The greater the total weight M of the rotor (23) and the crankshaft (25) is, the less likely the crankshaft (25) is to move vertically. The greater the parameter L1 / Vcc becomes, the smaller the parameter Vcc × sin(πL / L0) becomes.

[0090] According to the present embodiment, it is possible to further reduce the vertical movement of the crankshaft (25) caused by pressure fluctuations due to the resonance, thereby reducing noise generation.

[0091] According to the present embodiment, satisfying the above-described conditions can help reduce pressure fluctuations caused by the resonance, thereby reducing noise generation, even in a large-volume, multi-cylinder refrigerant compressor including the first cylinder (40) and the first roller (46), and the second cylinder (50) and the second roller (56), which tends to generate noise easily.

[0092] According to the present embodiment, the maximum number of revolutions of the rotor (23) is set to 100 rps or higher, which lowers the oil level and the resonance frequency. Therefore, even if the rotor (23) is rotated at a high speed and a collision with the resonance occurs, noise generation can be reduced.

[0093] According to the present embodiment, a refrigeration apparatus including the refrigerant compressor (10) can be provided.

[0094] According to the present embodiment, an air-conditioning system including the refrigeration apparatus (1) serving as an air-conditioning apparatus can be provided.<<Other Embodiments>>

[0095] While the embodiments and variations have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the claims. The elements according to the embodiments, the variations thereof, and the other embodiments may be combined and replaced with each other. In addition, the expressions of "first," "second," "third," . . . , in the specification and claims are used to distinguish the terms to which these expressions are given, and do not limit the number and order of the terms.INDUSTRIAL APPLICABILITY

[0096] As described above, the present disclosure is useful for a refrigerant compressor, a refrigeration apparatus, and an air-conditioning system.DESCRIPTION OF REFERENCE CHARACTERS

[0097] 1Refrigeration Apparatus 10Refrigerant Compressor 11Primary Space 12Secondary Space 13Casing 21Motor 23Rotor 25Crankshaft 27First Eccentric Portion (Eccentric Portion) 30Compression Mechanism 31Front Head (First Head) 38Oil Supply Mechanism 39Suction Port 40First Cylinder 41First Cylinder Chamber 46First Roller 50Second Cylinder 51Second Cylinder Chamber 56Second Roller 63First Discharge Port (Discharge Port) 70Cylinder 71Cylinder Chamber 76Roller 100Air-Conditioning System

Examples

embodiment -

- Advantages of Embodiment -

[0087]According to the present embodiment, by increasing the distance L1 so as to satisfy the condition of the expression (1) described above and thereby bringing the excitation position of the resonance closer to the node, pressure fluctuations caused by the resonance are decreased, which can reduce the collision of the crankshaft (25) with the first head (31), thereby reducing noise.

[0088]According to the present embodiment, by satisfying the condition of the expression (2) described above, pressure fluctuations caused by the resonance can be decreased, thereby reducing noise caused by the collision of the crankshaft (25) with the first head (31).

[0089]Specifically, the smaller the displacement volume Vcc is, the smaller the discharge amount of the refrigerant becomes and the smaller the excitation force of the resonance becomes. The closer the discharge port (63), serving as the excitation position of the resonance, is to the node of the resonance, the...

Claims

1. A refrigerant compressor using carbon dioxide as a refrigerant, the refrigerant compressor comprising: a crankshaft (25) extending along a first direction and having an eccentric portion (27); a motor (21) configured to rotate the crankshaft (25); a compression mechanism (30) coupled to the crankshaft (25) and configured to be driven by the crankshaft (25); and a casing (13) which houses the crankshaft (25), the motor (21), and the compression mechanism (30), and in which a primary space (11) below the motor (21) and a secondary space (12) above the motor (21) are formed, the compression mechanism (30) including: a first head (31) rotatably supporting the crankshaft (25); a cylinder (70) disposed adjacent to the first head (31) and including a cylinder chamber (71); and a roller (76) fixed to the eccentric portion (27) and configured to eccentrically rotate in the cylinder chamber (71), the eccentric portion (27) having an upper surface overlapping with a part of a lower surface of the first head (31) when viewed from the first direction, the crankshaft (25) being provided with, at a lower end portion thereof, an oil supply mechanism (38) including a suction port (39) through which oil stored in a lower end portion of the casing (13) is drawn, a displacement volume Vcc [cc] per rotation of the compression mechanism (30) and a distance L1 [mm] between the suction port (39) and a lower end of a member joined to the casing (13), among members constituting the compression mechanism (30), satisfying the following condition: L 1 / Vcc > 13 .

2. The refrigerant compressor of claim 1, wherein the compression mechanism (30) is provided with a discharge port (63) through which compressed refrigerant is discharged to the primary space (11), and a distance L0 [mm] between an upper end of the secondary space (12) and the suction port (39), a distance L [mm] between the discharge port (63) and a midpoint between the upper end of the secondary space (12) and the suction port (39), and a total weight M [kg] of a rotor (23) of the motor (21) and the crankshaft (25) satisfy the following condition: Vcc × sin πL / L 0 / M ≤ 0.90 .

3. The refrigerant compressor of claim 2, wherein the following condition is satisfied: Vcc × sin(πL / L0) / M ≤ 0.86.

4. The refrigerant compressor of any one of claims 1 to 3, wherein the cylinder (70) includes: a first cylinder (40) including a first cylinder chamber (41); and a second cylinder (50) including a second cylinder chamber (51), and the roller (76) includes: a first roller (46) housed in the first cylinder chamber (41); and a second roller (56) housed in the second cylinder chamber (51).

5. The refrigerant compressor of any one of claims 1 to 4, wherein a maximum number of revolutions of a rotor (23) of the motor (21) is 100 rps or higher.

6. A refrigeration apparatus comprising the refrigerant compressor (10) of any one of claims 1 to 5.

7. An air-conditioning system comprising the refrigeration apparatus (1) of claim 6, the refrigeration apparatus (1) being an air-conditioning apparatus configured to condition air in a predetermined target space.

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