ROTARY COMPRESSOR AND REFRIGERATION APPARATUS

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001]This is a continuation of International Application No. PCT/JP2024/000491 filed on Jan. 11, 2024, which claims priority under 35 U.S.C. § 119(a) to Patent Application No. 2023-036491, filed in Japan on Mar. 9, 2023, all of which are hereby expressly incorporated by reference into the present application.

BACKGROUND

Technical Field

[0002]The present disclosure relates to a rotary compressor and a refrigeration apparatus.

Background Information

[0003]Japanese Unexamined Patent Publication No. 2016-050549 discloses a scroll compressor including: a compression mechanism that compresses a refrigerant; a drive shaft (crankshaft) that drives the compression mechanism; and an electric motor that rotates the drive shaft.

[0004]An upper balance weight is provided unitary with the drive shaft. The upper balance weight is disposed between a housing of the compression mechanism and a rotor of the electric motor. The drive shaft is rotatably supported by an upper bearing provided to the housing and by a lower bearing. The drive shaft is connected, at a portion thereof between the upper bearing and the lower bearing, to the rotor of the electric motor.

SUMMARY

[0005]A first aspect of the present disclosure is directed to a rotary compressor including: a compression mechanism configured to compress a refrigerant; a drive shaft configured to drive the compression mechanism; and a motor configured to rotate the drive shaft, the rotary compressor including: a support member disposed between the compression mechanism and the motor and rotatably supporting the drive shaft; and a balance weight provided for the drive shaft and disposed between the compression mechanism and the motor, the support member including: a first support portion that supports the drive shaft on a side closer to the compression mechanism than the balance weight is; and a second support portion that supports the drive shaft on a side closer to the motor than the balance weight is.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006]FIG. 1 is a refrigerant circuit diagram illustrating a configuration of a refrigeration apparatus according to an embodiment.

[0007]FIG. 2 is a vertical sectional view illustrating a configuration of a scroll compressor.

[0008]FIG. 3 is a side sectional view illustrating configurations of a first housing body and a second housing body.

[0009]FIG. 4 is a vertical sectional view illustrating a configuration of a scroll compressor according to a variation.

DETAILED DESCRIPTION OF EMBODIMENT(S)

[0010]As illustrated in FIG. 1, a scroll compressor (10) serving as a rotary compressor is provided in a refrigeration apparatus (1). The refrigeration apparatus (1) includes a refrigerant circuit (la) filled with a refrigerant. The refrigerant circuit (la) includes the scroll 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 (la) performs a vapor compression refrigeration cycle.

[0011]The refrigeration apparatus (1) is an air conditioner. The air conditioner may be any of a cooling-only apparatus, a heating-only apparatus, or an air conditioner switchable between cooling and heating. In this case, the air conditioner has a switching mechanism (e.g., a four-way switching valve) that switches the direction of circulation of the refrigerant. The refrigeration apparatus (1) may be a water heater, a chiller unit, or a cooling apparatus that cools air in an internal space. The cooling apparatus cools air in an internal space of a refrigerator, a freezer, a container, or the like.

[0012]As illustrated in FIG. 2, the scroll compressor (10) includes a casing (20), a motor (25), and a compression mechanism (50). The casing (20) has a vertically elongated cylindrical shape and is configured as a sealed dome. The casing (20) houses the motor (25) and the compression mechanism (50).

[0013]The motor (25) includes a stator (26) and a rotor (27). The stator (26) is fixed to the inner circumferential surface of the casing (20). The rotor (27) is disposed inside the stator (26). A drive shaft (11) passes through the rotor (27). The rotor (27) is fixed to the drive shaft (11). A lower weight (28) is provided at a lower portion of the rotor (27). The lower weight (28) is covered with a lower cover (29).

[0014]The casing (20) has, at its bottom, an oil reservoir (21). The oil reservoir (21) stores a lubricant. A suction pipe (12) is connected to an upper portion of the casing (20). A discharge pipe (13) is connected to a barrel of the casing (20). An inflow end of the discharge pipe (13) communicates with a discharge space (23) that is above the motor (25).

[0015]The drive shaft (11) extends vertically along the center axis of the casing (20). The drive shaft (11) includes a main shaft portion (14), an eccentric portion (15), and a balance weight (18).

[0016]The eccentric portion (15) is provided at the upper end of the main shaft portion (14). The balance weight (18) is disposed between the compression mechanism (50) and the motor (25).

[0017]The main shaft portion (14) has a lower portion rotatably supported by a lower bearing (22). The lower bearing (22) is fixed to the inner circumferential surface of the casing (20). The lower bearing (22) is provided with a positive-displacement pump (24), for example. The main shaft portion (14) passes through a housing (30) serving as a support member, and is rotatably supported by a first support portion (35) and a second support portion (45) of the housing (30), which will be described later.

[0018]The housing (30) is fixed to the casing (20). The housing (30) is located above the motor (25). The compression mechanism (50) is located above the housing (30).

[0019]The housing (30) includes a first housing body (31) and a second housing body (41). The first housing body (31) is located closer to the compression mechanism (50) than the second housing body (41) is located.

[0020]The first housing body (31) is fixed to the inner circumferential surface of the casing (20) by shrink fitting, for example. The first housing body (31) may also be fixed to the inner circumferential surface of the casing (20) by bolting, welding, or the like.

[0021]The first housing body (31) includes a recess (32), a first fitting portion (34), and the first support portion (35). The recess (32) is formed by a depression of a portion of the upper surface of the first housing body (31). In the recess (32), a boss (73) of a movable scroll (70) is disposed, which will be described later.

[0022]The first fitting portion (34) is formed by a protrusion of a portion of the lower surface of the first housing body (31). To the first fitting portion (34), a second fitting portion (44) of the second housing body (41) is fitted. The second fitting portion (44) will be described later.

[0023]The first support portion (35) supports the drive shaft (11) on a side closer to the compression mechanism (50) than the balance weight (18) is. The first support portion (35) is formed by a portion of the first housing body (31) that is below the bottom surface of the recess (32). The first support portion (35) has a first through hole (36) passing through the first support portion (35) in its axial direction. A cylindrical first bearing (37) is provided in the first through hole (36). The first bearing (37) is, for example, a metal bearing. The first bearing (37) may be a rolling bearing.

[0024]The first support portion (35) rotatably supports the drive shaft (11) via the first bearing (37). The drive shaft (11) may be rotatably supported by the inner circumferential surface of the first through hole (36) of the first support portion (35), without providing the first bearing (37).

[0025]The first housing body (31) has, on its lower surface, screw holes (38). The multiple screw holes (38) are provided at intervals in the circumferential direction of the first housing body (31).

[0026]The second housing body (41) includes an accommodation recess (42), a flange (43), the second fitting portion (44), and the second support portion (45).

[0027]The accommodation recess (42) is formed by a depression of a portion of the upper surface of the second housing body (41). The accommodation recess (42) accommodates the balance weight (18). The balance weight (18) is rotatable in the accommodation recess (42).

[0028]The flange (43) protrudes radially outward from an upper end portion of the second housing body (41). The flange (43) has a plurality of insertion holes (48) corresponding to the plurality of screw holes (38) of the first housing body (31).

[0029]The second fitting portion (44) extends along the outer peripheral edge of the flange (43) and protrudes upward. The second fitting portion (44) is fitted to the first fitting portion (34), to restrict the radial movement of the second housing body (41) relative to the first housing body (31).

[0030]The second support portion (45) supports the drive shaft (11) on a side closer to the motor (25) than the balance weight (18) is. The second support portion (45) is formed by a portion of the second housing body (41) that is below the bottom surface of the accommodation recess (42). The second support portion (45) has a second through hole (46) passing through the second support portion (45) in its axial direction. A cylindrical second bearing (47) is provided in the second through hole (46). The second bearing (47) is, for example, a metal bearing. The second bearing (47) may be a rolling bearing.

[0031]The second support portion (45) rotatably supports the drive shaft (11) via the second bearing (47). The drive shaft (11) may be rotatably supported by the inner circumferential surface of the second through hole (46) of the second support portion (45), without providing the second bearing (47).

[0032]The first housing body (31) having the first support portion (35) and the second housing body (41) having the second support portion (45) are combined with each other, so that the balance weight (18) is surrounded by the first housing body (31) and the second housing body (41).

[0033]Specifically, as illustrated also in FIG. 3, the second fitting portion (44) of the second housing body (41) is fitted to the first fitting portion (34) of the first housing body (31). Then, fastening bolts (49) are inserted into the insertion holes (48) through the flange (43) and are screwed into the screw holes (38). As a result, the second housing body (41) is fastened and fixed to the first housing body (31).

[0034]Thus, it is possible to position the second support portion (45) relative to the first support portion (35) in the radial direction and to restrict the movement of the second support portion (45) in the radial direction. The second support portion (45) may be positioned relative to the first support portion (35) by providing one or more positioning pins (not shown), for example, without providing the first fitting portion (34) and the second fitting portion (44).

[0035]In a preferred embodiment, an axial length L1 of a portion of the drive shaft (11), which is supported by the first support portion (35), and an axial length L2 of a portion of the drive shaft (11), which is supported by the second support portion (45), are set so as to satisfy the condition L1≥L2.

[0036]This can increase the contact area between the first bearing (37) at the first support portion (35), which is located closer to the compression mechanism (50), and the drive shaft (11), effectively reducing warping of the drive shaft (11) caused by the centrifugal force exerted by the balance weight (18).

[0037]The compression mechanism (50) includes a fixed scroll (60) and a movable scroll (70). The fixed scroll (60) is fixed to the upper surface of the housing (30). The movable scroll (70) is disposed between the fixed scroll (60) and the housing (30).

[0038]The fixed scroll (60) includes a fixed end plate (61), a fixed wrap (62), and an outer peripheral wall (63). The outer peripheral wall (63) is substantially tubular. The outer peripheral wall (63) is erected at an outer edge of the front surface (the lower surface in FIG. 2) of the fixed end plate (61).

[0039]The fixed wrap (62) is spiral. The fixed wrap (62) is erected on a portion of the fixed end plate (61) inside the outer peripheral wall (63).

[0040]The fixed end plate (61) is located on an outer side and is continuous with the fixed wrap (62). The distal end surface of the fixed wrap (62) and the distal end surface of the outer peripheral wall (63) are substantially flush with each other. The fixed scroll (60) is fixed to the housing (30).

[0041]The movable scroll (70) includes a movable end plate (71), a movable wrap (72), and the boss (73). The movable wrap (72) is spiral. The movable wrap (72) is provided on the upper surface of the movable end plate (71). The movable wrap (72) meshes with the fixed wrap (62).

[0042]The boss (73) is provided at a central portion of the lower surface of the movable end plate (71). The eccentric portion (15) of the drive shaft (11) is inserted into the boss (73), whereby the drive shaft (11) is connected to the boss (73).

[0043]An Oldham coupling (55) is provided at an upper portion of the housing (30). The Oldham coupling (55) blocks the rotation of the movable scroll (70) on its axis. The Oldham coupling (55) is provided with a key (56). The key (56) protrudes toward the lower surface of the movable end plate (71) of the movable scroll (70). The lower surface of the movable end plate (71) of the movable scroll (70) has a keyway (57). The key (56) of the Oldham coupling (55) is slidably fitted to the keyway (57).

[0044]Although not shown, the Oldham coupling (55) is provided with another key toward the housing (30). The key toward the housing (30) is slidably fitted to a keyway (not shown) of the housing (30).

[0045]The compression mechanism (50) has a fluid chamber(S) into which the refrigerant flows. The fluid chamber(S) is formed between the fixed scroll (60) and the movable scroll (70). The movable scroll (70) is placed so that the movable wrap (72) meshes with the fixed wrap (62) of the fixed scroll (60). Here, the lower surface of the outer peripheral wall (63) of the fixed scroll (60) serves as a facing surface that faces the movable scroll (70). Meanwhile, the upper surface of the movable end plate (71) of the movable scroll (70) serves as a facing surface that faces the fixed scroll (60).

[0046]The outer peripheral wall (63) of the fixed scroll (60) has a suction port (64). The suction port (64) is open near the winding end of the fixed wrap (62). A downstream end of the suction pipe (12) is connected to the suction port (64).

[0047]The fixed end plate (61) of the fixed scroll (60) has, at its center, an outlet (65). The outlet (65) is open to the upper surface of the fixed end plate (61) of the fixed scroll (60). A high-pressure gas refrigerant discharged from the outlet (65) flows out into the discharge space (23) via a passage (not shown) formed in the housing (30).

[0048]An oil supply passage (16) is provided inside the drive shaft (11). The oil supply passage (16) extends vertically from the lower end to the upper end of the drive shaft (11). A lower end portion of the drive shaft (11) is connected to the pump (24). A lower end portion of the pump (24) is immersed in the oil reservoir (21). The pump (24) sucks up the lubricant from the oil reservoir (21) as the drive shaft (11) rotates, and delivers the lubricant to the oil supply passage (16). Through the oil supply passage (16), the lubricant in the oil reservoir (21) is supplied to: sliding surfaces between the lower bearing (22) and the drive shaft (11); sliding surfaces between the first bearing (37) and the drive shaft (11); and sliding surfaces between the second bearing (47) and the drive shaft (11), as well as to sliding surfaces between the boss (73) and the drive shaft (11). The oil supply passage (16) is open to the upper end surface of the drive shaft (11), to supply the lubricant to above the drive shaft (11).

[0049]The recess (32) of the housing (30) communicates with the oil supply passage (16) of the drive shaft (11) via the inside of the boss (73) of the movable scroll (70). The high-pressure lubricant is supplied to the recess (32), so that a high pressure equivalent to the discharge pressure of the compression mechanism (50) acts on the recess (32). The movable scroll (70) is pressed onto the fixed scroll (60) by the high pressure that acts on the recess (32).

[0050]An oil passage (not shown) is provided inside the housing (30) and inside the fixed scroll (60). Through the oil passage, the high-pressure lubricant in the recess (32) is supplied to the facing surfaces of the movable end plate (71) of the movable scroll (70) and the outer peripheral wall (63) of the fixed scroll (60).

Operation

[0051]A basic operation of the scroll compressor (10) will be described. In FIG. 2, when the motor (25) is activated, the drive shaft (11), to which the rotor (27) is fixed, is driven to rotate. Since the rotation of the movable scroll (70) on its own axis is blocked by the Oldham coupling (55), the movable scroll (70) makes an orbiting motion about the axis of the drive shaft (11).

[0052]As the movable scroll (70) makes the orbiting motion, the refrigerant is compressed in the fluid chamber(S). The high-pressure gas refrigerant compressed in the fluid chamber(S) is discharged through the outlet (65) and flows out into the discharge space (23) via the passage (not shown) formed in the housing (30). The high-pressure gas refrigerant in the discharge space (23) is discharged outside the casing (20) via the discharge pipe (13).

[0053]As the drive shaft (11) rotates, the high-pressure lubricant in the oil reservoir (21) is sucked up by the pump (24), flows upward through the oil supply passage (16) of the drive shaft (11), and flows out through the opening at the upper end of the eccentric portion (15) of the drive shaft (11) into the inside of the boss (73) of the movable scroll (70).

[0054]The lubricant supplied to the boss (73) flows out into the recess (32) of the housing (30) through a gap between the eccentric portion (15) of the drive shaft (11) and the boss (73). As a result, in the recess (32) of the housing (30), a high pressure equivalent to the discharge pressure of the compression mechanism (50) is generated. Due to the high pressure in the recess (32), the movable scroll (70) is pressed onto the fixed scroll (60).

Advantages of Embodiment

[0055]According to the features of the present embodiment, the drive shaft (11) is supported on both sides, i.e., on the side closer to the compression mechanism (50) than the balance weight (18) is and on the side closer to the motor (25) than the balance weight (18) is. This can reduce warping of the drive shaft (11) caused by the centrifugal force exerted by the balance weight (18). It is thus possible to reduce a local increase in surface pressure at the drive shaft (11) and improve the reliability, allowing the scroll compressor (10) to operate at high speed.

[0056]According to the features of the present embodiment, the axial length of the portion of the drive shaft (11), which is supported by the first support portion (35), is designed to be equal to or longer than the axial length of the portion of the drive shaft (11), which is supported by the second support portion (45). This can increase the contact area between the first support portion (35), which is located closer to the compression mechanism (50), and the drive shaft (11), effectively reducing warping of the drive shaft (11) caused by the centrifugal force exerted by the balance weight (18).

[0057]According to the features of the present embodiment, the drive shaft (11) is supported by the first bearing (37) and the second bearing (47), allowing the drive shaft (11) to rotate smoothly.

[0058]According to the features of the present embodiment, the first housing body (31) including the first support portion (35) and the second housing body (41) including the second support portion (45) are respectively constructed from separate members, and this improves the assembly workability. In addition, combining the first housing body (31) and the second housing body (41) with each other allows the balance weight (18) to be surrounded by the first housing body (31) and the second housing body (41). This can reduce the disturbance of the flow of the refrigerant in the casing (20) due to the rotation of the balance weight (18).

[0059]According to the features of the present embodiment, it is possible to provide the refrigeration apparatus (1) including: the rotary compressor (10); and the refrigerant circuit (la) through which a refrigerant compressed by the rotary compressor (10) flows.

Variation

[0060]In the following description, the same reference characters denote the same components as those of the foregoing embodiment, and the description is focused only on the difference.

[0061]As illustrated in FIG. 4, the drive shaft (11) includes the balance weight (18). The balance weight (18) is disposed between the compression mechanism (50) and the motor (25).

[0062]The balance weight (18) includes a weight protrusion (19). The weight protrusion (19) is formed by a protrusion of a portion of the upper surface of the balance weight (18). The weight protrusion (19) extends along the outer peripheral edge of the balance weight (18) and protrudes upward.

[0063]The housing (30) includes the first housing body (31) and the second housing body (41). The balance weight (18) is accommodated in the accommodation recess (42) of the second housing body (41).

[0064]The first housing body (31) has, on its lower surface, a ring groove (39). The weight protrusion (19) is positioned so as to be inserted into the ring groove (39). The ring groove (39) is designed to have a groove width and a groove depth such that the weight protrusion (19) does not interfere with the first housing body (31) when the balance weight (18) rotates.

[0065]Thus, providing the weight protrusion (19) along the outer peripheral edge of the balance weight (18) can increase the overall weight of the balance weight (18).

[0066]While the embodiment and the variation thereof 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 embodiment, the variations thereof, and the other embodiments may be combined and replaced with each other. In addition, the modifiers such as “first,” “second,” “third,” and so on in the description and claims are used to distinguish the terms that they modify, and do not limit the number and order of those terms.

[0067]As can be seen from the foregoing description, the present disclosure is useful for a rotary compressor and a refrigeration apparatus.