SCREW COMPRESSOR AND REFRIGERATION APPARATUS

Abstract

A compressor includes a casing having a bottom portion with a reservoir to store oil, an electric motor housed in the casing, a compression mechanism disposed between the electric motor and the reservoir, and a resonance muffler provided in the compression mechanism. The compression mechanism compresses sucked gas refrigerant and to discharges the compressed gas refrigerant into the casing. A refrigerant space is formed above the reservoir in the casing. The refrigerant space is configured so that the gas refrigerant discharged from the compression mechanism flows through. The muffler includes a cavity in which a resonance chamber is formed, and a first opening communicating with the resonance chamber and opening to the refrigerant space. The first opening is formed on a lower surface or an outer peripheral surface of the compression mechanism.

Description

BACKGROUND

Technical Field

The present disclosure relates to a compressor and a refrigeration apparatus.

Background Art

Japanese Unexamined Patent Publication No. 2014-118862 discloses a compressor having a Helmholtz muffler. The compressor of Patent Document 1 has a drive shaft extending in the top-bottom direction in a casing, a motor attached to an upper portion of the drive shaft, and a compression mechanism attached to a lower portion of the drive shaft.

The Helmholtz muffler of Japanese Unexamined Patent Publication No. 2014-118862 has a resonance chamber having an opening which is open between the compression mechanism and a rotor of the motor. At least part of an inner wall surface of the resonance chamber is formed by an outer peripheral surface of the drive shaft. The opening is formed near the drive shaft, and thus resonance with a high frequency generated near the drive shaft in the casing can be reduced.

SUMMARY

A first aspect is directed to a compressor including a casing having a bottom portion with a reservoir configured to store oil, an electric motor housed in the casing, a compression mechanism disposed between the electric motor and the reservoir, and a resonance muffler provided in the compression mechanism. The compression mechanism is configured to compress sucked gas refrigerant and to discharge the compressed gas refrigerant into the casing. A refrigerant space is formed above the reservoir in the casing. The refrigerant space is configured so that the gas refrigerant discharged from the compression mechanism flows therethrough. The muffler includes a cavity in which a resonance chamber is formed, and a first opening communicating with the resonance chamber and opening to the refrigerant space. The first opening is formed on a lower surface or an outer peripheral surface of the compression mechanism.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic piping system diagram of a refrigeration apparatus including a compressor according to a first embodiment.

FIG. 2 is a longitudinal sectional view illustrating the schematic configuration of the compressor.

FIG. 3 is an enlarged sectional view of a periphery of a muffler.

FIG. 4 corresponds to FIG. 3 and shows a second variation of the first embodiment.

FIG. 5 corresponds to FIG. 3 and shows a second embodiment.

FIG. 6 corresponds to FIG. 3 and shows a first variation of the second embodiment.

FIG. 7 corresponds to FIG. 3 and shows a third embodiment.

FIG. 8 corresponds to FIG. 3 and shows a second variation of the third embodiment.

FIG. 9 is an enlarged sectional view of a periphery of a compression mechanism where an oil level is low according to a fourth embodiment.

FIG. 10 corresponds to FIG. 9 and shows a case where the oil level is high according to the fourth embodiment.

FIG. 11 corresponds to FIG. 3 and shows another embodiment.

DETAILED DESCRIPTION OF EMBODIMENT(S)

Embodiments of the present disclosure will be described in detail below with reference to the drawings. The present disclosure is not limited to the embodiments shown below, and various changes can be made within the scope without departing from the technical concept of the present disclosure. Each of the drawings is intended to illustrate the present disclosure conceptually, and dimensions, ratios, or numbers may be exaggerated or simplified as necessary for the sake of ease of understanding.

FIRST EMBODIMENT

A compressor (100) of a first embodiment will be described.

(1) Overview of Refrigeration Apparatus

The compressor (100) of this embodiment is provided in a refrigeration apparatus (1). As illustrated in FIG. 1, the refrigeration apparatus (1) has a refrigerant circuit (1a) filled with refrigerant. The refrigerant circuit (1a) has the compressor (100), a radiator (3), a decompression mechanism (4), and an evaporator (5). The decompression mechanism (4) is an expansion valve. The refrigerant circuit (1a) performs a vapor compression refrigeration cycle.

In the refrigeration cycle, the refrigerant compressed by the compressor (100) dissipates heat to air in the radiator (3). The refrigerant having dissipated heat is decompressed by the decompression mechanism (4) and evaporates in the evaporator (5). The evaporated refrigerant is sucked into the compressor (100).

The refrigeration apparatus (1) is an air conditioner. The air conditioner may be a cooling apparatus, a heating apparatus, or an air conditioner switchable between cooling and heating. In this case, the air conditioner has a switching mechanism (e.g., 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 a refrigerator, a freezer, or a container, for example.

(2) Compressor

As illustrated in FIG. 2, the compressor (100) of this embodiment is a hermetic compressor. The compressor (100) is a one-cylinder rotary compressor. The compressor (100) sucks a low-pressure gas refrigerant and compresses the sucked gas refrigerant. The compressor (100) discharges the compressed high-pressure gas refrigerant.

The compressor (100) includes a casing (10), an electric motor (20), a drive shaft (30), and a compression mechanism (40). The casing (10) houses the electric motor (20), the drive shaft (30), and the compression mechanism (40).

(2-1) Casing

The casing (10) is a hermetically-closed container standing upright and formed in a cylindrical shape. The casing (10) includes a barrel (11), an upper end plate (12), and a lower end plate (13). The barrel (11) has a cylindrical shape. The upper end plate (12) closes the upper end of the barrel (11). The lower end plate (13) closes the lower end of the barrel (11).

A suction pipe (14) is attached to a lower portion of the barrel (11). The suction pipe (14) passes through the barrel (11) of the casing (10), and is connected to the compression mechanism (40). A discharge pipe (15) is attached to the upper end plate (12). The discharge pipe (15) passes through the top of the casing (10), and is open to the inside of the casing (10).

A reservoir (16) for storing oil for lubricating sliding portions of the compression mechanism (40) etc. is formed in the bottom part of the casing (10).

A refrigerant space(S) through which a gas refrigerant discharged from the compression mechanism (40) flows is formed inside the casing (10). The refrigerant space(S) is formed above the reservoir (16) in the casing (10). In other words, the bottom surface facing the refrigerant space(S) is an oil surface of the reservoir (16).

(2-2) Electric Motor

The electric motor (20) is disposed at an upper portion in the casing (10). The electric motor (20) includes a stator (21) and a rotor (22). The stator (21) is fixed to the barrel (11) of the casing (10). The drive shaft (30) is inserted into the rotor (22).

(2-3) Drive Shaft

The drive shaft (30) extends in the axial direction (the top-bottom direction) of the casing (10) from an upper portion of the barrel (11) of the casing (10) to the bottom portion of the casing (10). The drive shaft (30) is rotated by the electric motor (20). The drive shaft (30) has a main shaft portion (31), a secondary shaft portion (32), and an eccentric portion (33). In the drive shaft (30), the main shaft portion (31), the eccentric portion (33), and the secondary shaft portion (32) are arranged in sequence from top to bottom. In the drive shaft (30), the main shaft portion (31), the eccentric portion (33), and the secondary shaft portion (32) are integrated with each other.

The main shaft portion (31) and the secondary shaft portion (32) each have a circular columnar shape. The main shaft portion (31) and the secondary shaft portion (32) are arranged coaxially with each other. The rotor (22) of the electric motor (20) is attached to an upper portion of the main shaft portion (31). A lower portion of the main shaft portion (31) is inserted into a front head (45) described later. The secondary shaft portion (32) is inserted into a rear head (46) described later. The drive shaft (30) is configured so that the main shaft portion (31) is rotatably supported by the front head (45) and the secondary shaft portion (32) is rotatably supported by the rear head (46).

The eccentric portion (33) has a circular columnar shape. The eccentric portion (33) has a larger diameter than those of the main shaft portion (31) and the secondary shaft portion (32). The center axis of the eccentric portion (33) is parallel with the center axis of rotation of the main shaft portion (31) and the secondary shaft portion (32). The center axis of the eccentric portion (33) is eccentric with respect to the main shaft portion (31) and the secondary shaft portion (32). The eccentric portion (33) is inserted into a piston (44). The eccentric portion (33) supports the piston (44).

A centrifugal pump (34) is provided at the lower end of the secondary shaft portion (32). The centrifugal pump (34) is immersed in the reservoir (16). An oil supply passage (not shown) is formed in the drive shaft (30). When the drive shaft (30) rotates, the oil in the reservoir (16) is supplied to a bearing of the drive shaft (30) and the sliding portions of the compression mechanism (40) through the oil supply passage.

(2-4) Compression Mechanism

The compression mechanism (40) is a so-called oscillating-piston rotary compression mechanism. The compression mechanism (40) is driven by the electric motor (20) through the drive shaft (30). The compression mechanism (40) is disposed between the electric motor (20) and the reservoir (16) in the casing (10). In other words, the compression mechanism (40) is disposed below the electric motor (20).

The compression mechanism (40) has one front head (45), one rear head (46), one cylinder (41), and one piston (44). In the compression mechanism (40), the front head (45), the cylinder (41), and the rear head (46) are arranged in sequence from top to bottom so as to overlap with each other. In other words, in the compression mechanism (40), a plurality of members is arranged so as to overlap with each other. The front head (45), the cylinder (41), and the rear head (46) are fastened to each other by a plurality of bolts (not shown). The compression mechanism (40) is fixed to the casing (10) by the cylinder (41) being fixed to the inner peripheral surface of the barrel (11) through a mounting plate (not shown).

(2-4-1) Cylinder and Piston

The cylinder (41) has a thick disk shape. The cylinder (41) is disposed concentrically with the barrel (11) of the casing (10). A cylinder bore (42) is formed in a center portion of the cylinder (41). The piston (44) is disposed in the cylinder bore (42). The piston (44) has a thick cylindrical shape. The eccentric portion (33) of the drive shaft (30) is inserted into the piston (44).

In the compression mechanism (40), a compression chamber (C) is formed between the wall surface of the cylinder bore (42) and the outer peripheral surface of the piston (44). The compression mechanism (40) is provided with a blade partitioning the compression chamber (C) into a high-pressure chamber and a low-pressure chamber.

The cylinder (41) has a suction port (43). The suction port (43) extends in the radially outward direction of the cylinder from the wall surface of the cylinder bore (42). The suction port (43) is a hole having a circular section. The suction port (43) communicates with the low-pressure chamber of the compression chamber (C). The suction port (43) opens on the outer surface of the cylinder (41). The suction pipe (14) is inserted into the suction port (43).

(2-4-2) Front Head and Rear Head

The front head (45) is a member that covers the opening surface of the upper end of the cylinder (41) (one end of the cylinder (41) in the axial direction). The front head (45) has a first end plate portion (45a) and a first boss portion (45b). The first end plate portion (45a) has a disk shape. The first end plate portion (45a) is disposed so as to face the electric motor (20) in the axial direction. The first boss portion (45b) has a cylindrical shape. The first boss portion (45b) extends upward (toward the electric motor (20)) from the first end plate portion (45a) along the outer peripheral surface of the drive shaft (30). A circular hole is formed in a center portion of the front head (45). In the hole of the front head (45), the main shaft portion (31) of the drive shaft (30) is disposed with a sliding bearing sandwiched between the front head (45) and the main shaft portion (31).

The rear head (46) is a member that covers the opening surface of the lower end of the cylinder (41) (the other end of the cylinder (41) in the axial direction). The rear head (46) has a second end plate portion (46a) and a second boss portion (46b). The second end plate portion (46a) has a disk shape. The second end plate portion (46a) is disposed so as to face the first end plate portion (45a) in the axial direction. The second boss portion (46b) has a cylindrical shape. The second boss portion (46b) extends downward from the second end plate portion (46a) along the outer peripheral surface of the drive shaft (30). A circular hole is formed in a center portion of the rear head (46). In the hole of the rear head (46), the secondary shaft portion (32) of the drive shaft (30) is disposed with a sliding bearing sandwiched between the rear head (46) and the secondary shaft portion (32).

In this embodiment, the front head (45) corresponds to a first closing member of the present disclosure, and the rear head (46) corresponds to a second closing member of the present disclosure.

A discharge passage (not shown) is formed in the first end plate portion (45a) of the front head (45). The discharge passage is a passage for discharging the refrigerant compressed in the compression chamber (C) of the cylinder (41) to a space present above the compression mechanism (40). The discharge passage communicates with the high-pressure chamber of the compression chamber (C). A cover member (47) is provided on an upper portion of the front head (45). The cover member (47) is provided to cover the upper surface of the first end plate portion (45a) and the outer peripheral surface of a lower portion of the first boss portion (45b). A muffler space for reducing pulsation of the refrigerant discharged through the discharge passage is formed inside the cover member (47).

(3) Muffler

As illustrated in FIGS. 2 and 3, the compression mechanism (40) has a resonance muffler (50). The resonance muffler (50) is provided to reduce noise produced by resonance in the casing (10). The resonance muffler (50) of this embodiment is a Helmholtz muffler (50). The muffler (50) of this embodiment has a cavity (51), a first communication passage (52), and a first opening (53).

The cavity (51) is a space formed in a vertically-long circular columnar shape. The cavity (51) extends in the direction in which the plurality of members constituting the compression mechanism (40) overlap with each other (the top-bottom direction). The cavity (51) is formed across the first end plate portion (45a) of the front head (45), the cylinder (41), and the second end plate portion (46a) of the rear head (46).

Specifically, the lower end surface of the first end plate portion (45a) of the front head (45) has a first recess (61) that is recessed upward. The upper end surface of the second end plate portion (46a) of the rear head (46) has a second recess (62) that is recessed downward. The cylinder (41) has a through hole (63) penetrating therethrough in the top-bottom direction (the axial direction). The first recess (61) of the front head (45), the through hole (63) of the cylinder (41), and the second recess (62) of the rear head (46) have the same diameter and are arranged coaxially.

Internal spaces of the first recess (61) of the front head (45), the through hole (63) of the cylinder (41), and the second recess (62) of the rear head (46) constitute the cavity (51). In other words, each internal space of the first recess (61) of the front head (45), the through hole (63) of the cylinder (41), and the second recess (62) of the rear head (46) constitutes part of the cavity (51). In this embodiment, the front head (45) and the rear head (46) correspond to a first member (E1) of the present disclosure, and the cylinder (41) corresponds to a second member (E2) of the present disclosure.

A resonance chamber (R) is formed in the cavity (51). In this embodiment, the cavity (51) as a whole constitutes the resonance chamber (R).

The first communication passage (52) communicates with the resonance chamber (R). In this embodiment, the first communication passage (52) communicates with the cavity (51). The first communication passage (52) has a circular section. The first communication passage (52) has a sectional area smaller than that of the cavity (51). The first communication passage (52) extends radially outward from the cavity (51) toward the outer peripheral surface of the compression mechanism (40). Specifically, the first communication passage (52) consists of a groove extending radially outward from the inner peripheral surface of the second recess (62) of the second end plate portion (46a) of the rear head (46) toward the outer peripheral surface of the second end plate portion (46a). This groove is formed on the upper end surface of the second end plate portion (46a). The first communication passage (52) is formed by the groove formed on the upper end surface of the second end plate portion (46a) and the lower end surface of the cylinder (41). The first communication passage (52) communicates with a lower part of the cavity (51).

The first opening (53) is formed at an end portion of the first communication passage (52) opposite to the cavity (51). The first opening (53) is formed on the outer peripheral surface of the rear head (46). In other words, the first opening (53) is formed on the outer peripheral surface of the compression mechanism (40). The first opening (53) is open to the inside of the casing (10). Specifically, the first opening (53) is open to the refrigerant space(S). The first opening (53) is open to a portion below the cylinder (41) in the casing (10). The first opening (53) faces radially outward.

The first communication passage (52) allows the cavity (51) to communicate with the refrigerant space(S). In other words, the first communication passage (52) allows the cavity (51) to communicate with a space below the cylinder (41) in the casing (10). The cavity (51) does not communicate with the discharge passage formed in the compression mechanism (40).

In the muffler (50) of this embodiment, the volume of the resonance chamber (R), the sectional area of the first communication passage (52) (the area of a section parallel with the drive shaft (30)), and the length of the first communication passage (52) (the length in the direction perpendicular to the drive shaft (30)) are set so that the resonance frequency (natural frequency) of the muffler (50) is equal to the frequency of resonance produced near the oil surface in the reservoir (16).

(4) Operation of Compressor

Next, operation of the compressor (100) will be described.

When electric power is supplied to the electric motor (20), the rotor (22) is rotated by a rotating magnetic field produced inside the stator (21). When the rotor (22) rotates, the drive shaft (30) rotates. When the drive shaft (30) rotates, the piston (44) of the compression mechanism (40) coupled to the drive shaft (30) oscillates in the compression chamber (C). Accordingly, the volumes of the low-pressure chamber and high-pressure chamber of the compression chamber (C) change periodically, and the compression chamber (C) performs a suction operation, a compression operation, and a discharge operation of refrigerant continuously.

The refrigerant sucked into the low-pressure chamber of the compression chamber (C) through the suction pipe (14) is compressed in the high-pressure chamber of the compression chamber (C), and then is discharged into the muffler space in the cover member (47) through the discharge passage. The refrigerant discharged into the muffler space is discharged into a space between the compression mechanism (40) and the electric motor (20) in the casing (10) through the through hole formed in the cover member (47). The refrigerant discharged from the cover member (47) passes through a space between the stator (21) and rotor (22) (a so-called air gap) of the electric motor (20), reaches a space above the electric motor (20), and is discharged to the outside of the casing (10) through the discharge pipe (15).

In the hermetically-closed compressor (100) of this embodiment, pressure considerably fluctuates near both axial end portions of the casing (10), and noise is likely to be produced by resonance. The oil surface in the reservoir (16) formed in the bottom portion of the casing (10) is usually positioned at a level that allows part or whole of the compression mechanism (40) to be immersed in the oil in order to lubricate the sliding portion and the like of the compression mechanism (40). Thus, noise is likely to be produced by resonance around the compression mechanism (40), that is, near the oil surface in the casing (10). In contrast, in this embodiment, the first opening (53) of the Helmholtz muffler (50) formed in the compression mechanism (40) is formed on the outer peripheral surface of the compression mechanism (40). Accordingly, noise produced by resonance near the oil surface can be efficiently reduced.

(5) Features

(5-1)

The first opening (53) of the muffler (50) of this embodiment is formed on the outer peripheral surface of the compression mechanism (40). Accordingly, vibration by resonance near the oil surface in the casing (10) can be reduced. As a result, noise produced by this vibration can be reduced.

(5-2)

The front head (45) of this embodiment has the first recess (61), and the rear head (46) has the second recess (62). The internal spaces of the first recess (61) and the second recess (62) constitute part of the cavity (51). Part of the cavity (51) is constituted by the internal spaces of the first recess (61) and the second recess (62), and thus the cavity (51) can be formed in the front head (45) and the rear head (46) by simple processing.

(5-3)

The cylinder (41) of this embodiment has the through hole (63) penetrating the cylinder (41) in the top-bottom direction. The internal space of the through hole (63) constitutes part of the cavity (51). Part of the cavity (51) is constituted by the through hole (63), and thus the cavity (51) can be formed in the cylinder by simple processing.

(5-4)

The cavity (51) of this embodiment is formed across the cylinder (41), the front head (45), and the rear head (46). Accordingly, the cavity (51) can be formed without additional members for the compression mechanism (40).

(6) Variations

The above embodiment may be modified to the following variations. Basically, differences from the above embodiment will be described below.

(6-1) First Variation

In the compressor (100) of this embodiment, the groove constituting the first communication passage (52) of the muffler (50) may be formed on the lower end surface of the first end plate portion (45a) of the front head (45), the upper end surface of the cylinder (41), or the lower end surface of the rear head (46).

(6-2) Second Variation

In the compressor (100) of this embodiment, the first communication passage (52) of the muffler (50) may communicate with a lower end portion of the cavity (51). Specifically, for example, as illustrated in FIG. 4, if the cavity (51) consists of the internal spaces of the first recess (61) of the front head (45) and the through hole (63) of the cylinder (41), the first communication passage (52) may be constituted by a groove formed on the lower end surface of the cylinder (41).

SECOND EMBODIMENT

A second embodiment will be described. A compressor (100) of this embodiment has a first communication passage (52) and a first opening (53) different from those of the compressor (100) of the first embodiment. Here, the differences between the first communication passage (52) and the first opening (53) of this embodiment and the first communication passage (52) and the first opening (53) of the first embodiment will be described.

(1) First Communication Passage and First Opening

As illustrated in FIG. 5, the first communication passage (52) of this embodiment extends downward from the cavity (51) toward the lower surface of the compression mechanism (40). Specifically, the first communication passage (52) consists of a hole extending downward from the bottom surface of the second recess (62) in the second end plate portion (46a) of the rear head (46) toward the lower end surface of the second end plate portion (46a). The hole opens on the lower end surface of the second end plate portion (46a). The first communication passage (52) communicates with the lower surface of the cavity (51).

The first opening (53) is formed at an end portion of the first communication passage (52) opposite to the cavity (51). The first opening (53) is formed on the lower surface of the rear head (46). In other words, the first opening (53) is formed on the lower surface of the compression mechanism (40). The first opening (53) faces the oil surface in the reservoir (16).

(2) Features

The first opening (53) of the muffler (50) of this embodiment is formed on the lower surface of the compression mechanism (40). Accordingly, vibration by resonance near the oil surface in the casing (10) can be reduced. As a result, noise produced by this vibration can be reduced.

(3) Variations

The above embodiment may be modified to the following variations. Basically, differences from the above embodiment will be described below.

(3-1) First Variation

As illustrated in FIG. 6, in the compressor (100) of this embodiment, the resonance muffler (50) may be a side-branch muffler. Specifically, the muffler (50) of this embodiment may consist of the cavity (51) and the first opening (53). In other words, the muffler (50) of this variation does not have the first communication passage (52) unlike the above embodiment. The first opening (53) is open to the lower surface of the compression mechanism (40). The first opening (53) faces downward. The first opening (53) faces the oil surface in the reservoir (16).

If the first opening (53) facing downward is formed on a member other than the lowermost member among the members constituting the compression mechanism (40) as in this variation, the first opening (53) is formed on a portion where the member on which the first opening (53) is formed does not overlap a member disposed below the member on which the first opening (53) is formed.

(3-2) Second Variation

In the compressor (100) of this embodiment, the hole constituting the first communication passage (52) of the muffler (50) may be formed across a plurality of members constituting the compression mechanism (40). For example, if the cavity (51) is formed across the front head (45) and the cylinder (41), the first communication passage (52) may be formed across the cylinder (41) and the rear head (46). In this case, the first opening (53) is formed on the lower end surface of the rear head (46).

THIRD EMBODIMENT

A third embodiment will be described. A compressor (100) of this embodiment has a muffler (50) different from that of the compressor (100) of the first embodiment. Here, the differences between the muffler (50) of this embodiment and the muffler (50) of the first embodiment will be described.

(1) Muffler

As illustrated in FIG. 7, the muffler (50) of this embodiment has the cavity (51), the first communication passage (52), the first opening (53), a second communication passage (54), and a second opening (55). In other words, the muffler (50) of this embodiment further has the second communication passage (54) and the second opening (55) unlike the muffler (50) of the first embodiment. Similarly to the first embodiment, the cavity (51) of this embodiment is formed across the first end plate portion (45a) of the front head (45), the cylinder (41), and the second end plate portion (46a) of the rear head (46). Specifically, internal spaces of the first recess (61) of the front head (45), the through hole (63) of the cylinder (41), and the second recess (62) of the rear head (46) constitute the cavity (51).

The first communication passage (52) consists of a groove extending radially outward from the inner peripheral surface of the first recess (61) of the first end plate portion (45a) of the front head (45) toward the outer peripheral surface of the first end plate portion (45a). This groove is formed on the lower end surface of the first end plate portion (45a). The first communication passage (52) is formed by the groove formed on the lower end surface of the first end plate portion (45a) and the upper end surface of the cylinder (41). The first communication passage (52) communicates with the upper part of the cavity (51).

The first opening (53) is formed on the outer peripheral surface of the front head (45). In other words, the first opening (53) is formed on the outer peripheral surface of the compression mechanism (40). The first opening (53) is open to the inside of the casing (10). Specifically, the first opening (53) is open to the refrigerant space(S). The first opening (53) is open to a portion above the cylinder (41) in the casing (10). The first opening (53) faces radially outward.

The first communication passage (52) allows the cavity (51) to communicate with the refrigerant space(S). In other words, the first communication passage (52) allows the cavity (51) to communicate with a space between the compression mechanism (40) and the electric motor (20) in the casing (10).

The second communication passage (54) communicates with the cavity (51). The second communication passage (54) is a passage through which the oil in the reservoir (16) flows in and out. The second communication passage (54) has a circular section. The second communication passage (54) has a sectional area smaller than that of the cavity (51). The second communication passage (54) extends radially outward from the cavity (51) toward the outer peripheral surface of the compression mechanism (40). Specifically, the second communication passage (54) consists of a groove extending radially outward from the inner peripheral surface of the second recess (62) of the second end plate portion (46a) of the rear head (46) toward the outer peripheral surface of the second end plate portion (46a). The groove is formed on the upper end surface of the second end plate portion (46a). The first communication passage (54) is formed by the groove formed on the upper end surface of the second end plate portion (46a) and the lower end surface of the cylinder (41). The second communication passage (54) communicates with the lower part of the cavity (51).

The second opening (55) is formed at an end portion of the second communication passage (54) opposite to the cavity (51). The second opening (55) is formed on the outer peripheral surface of the rear head (46). In other words, the second opening (55) is formed on the outer peripheral surface of the compression mechanism (40). The second opening (55) faces radially outward.

The second communication passage (54) allows the cavity (51) to communicate with a space below the cylinder (41) in the casing (10). The second opening (55) is formed below the first opening (53).

Here, the level of oil stored in the reservoir (16) of the casing (10) changes according to the operation state of the compressor (100). As illustrated in FIG. 7, if the oil level A in the reservoir (16) is above the second opening (55), the oil in the reservoir (16) flows into the cavity (51) through the second opening (55). The oil having flowed into the cavity (51) flows to the same level as that of oil in the reservoir (16). In this case, the bottom surface of the resonance chamber (R) in the cavity (51) consists of the oil surface. Accordingly, the Helmholtz muffler (50) of this embodiment serves a silencing function using the first communication passage (52) and the resonance chamber (R) that has the bottom surface consisting of the oil surface.

When the oil level A in the reservoir (16) rises, the oil further flows into the cavity (51) through the second opening (55), and the volume of the resonance chamber (R) of the muffler (50) decreases. When the volume of the resonance chamber (R) decreases, the resonance frequency of the muffler (50) increases. In contrast, when the oil level in the reservoir (16) lowers, the oil flows out of the cavity (51) through the second opening (55), and the volume of the resonance chamber (R) increases. When the volume of the resonance chamber (R) increases, the resonance frequency of the muffler (50) decreases. In this manner, the muffler (50) has the second opening (55), and thus the resonance frequency of the muffler (50) changes as the oil level in the reservoir (16) changes. If the oil level in the reservoir (16) is below the second opening (55), the muffler (50) does not serve a silencing function.

In the hermetically-closed compressor (100), the resonance frequency in the casing (10) changes as the oil level in the reservoir (16) changes. Specifically, for example, if the oil level is low, such as if the oil level is below the compression mechanism (40), resonance with a low frequency (about 830 Hz) is generated in the casing (10). In contrast, for example, if the oil level is high, such as if the oil level is at a substantially middle part of the cylinder (41) of the compression mechanism (40), resonance with a high frequency (about 1.3 kHz to 1.4 kHz) is generated in the casing (10).

In this embodiment, the compression mechanism (40) of the hermetically-closed compressor (100) includes the muffler (50) having the second opening (55). Accordingly, if the oil level in the reservoir (16) is low, resonance with a low frequency in the casing (10) can be reduced by the muffler (50) having the resonance chamber (R) that has a larger volume due to fluctuation in the oil level. In contrast, if the oil level in the reservoir (16) is high, resonance with a high frequency in the casing (10) can be reduced by the muffler (50) having the resonance chamber (R) that has a smaller volume due to fluctuation in the oil level.

Here, as described above, the level of oil stored in the reservoir (16) of the casing (10) changes according to the operation state of the compressor (100). The first opening (53) of this embodiment is formed below an initial supply position (A1) illustrated in FIG. 7, which is a position of the oil surface in the reservoir (16) reached at the time of shipment of the compressor (100). This initial supply position (A1) is a position of the oil surface reached by the amount of oil initially supplied to the casing (10) at the time of shipment of the compressor (100). When the oil surface in the reservoir (16) is at the initial supply position (A1), the oil flows into the cavity (51) also through the first opening (53), and the cavity (51) is filled with the oil. At this time, the muffler (50) does not serve a silencing function.

When the position of the oil surface in the reservoir (16) lowers to a position below the first opening (53) as the compressor (100) operates, the first opening (53) communicates with the refrigerant space(S). By the first opening (53) communicating with the refrigerant space(S), the cavity (51) of the muffler (50) communicates with the refrigerant space(S) and the muffler (50) serves a silencing function. Accordingly, noise with a low frequency that is produced as the oil level in the reservoir (16) lowers can be reduced.

(2) Features

(2-1)

The muffler (50) of this embodiment has the second opening (55) which communicates with the cavity (51) and through which the oil flows in and out. The second opening (55) is formed below the first opening (53).

When the oil level in the reservoir (16) rises and the oil flows into the cavity (51) through the second opening (55), the bottom surface of the resonance chamber (R) is constituted by the oil surface. The second opening (55) is formed below the first opening (53), and thus the Helmholtz muffler (50) serves a silencing function using the first communication passage (52) and the resonance chamber (R).

When the oil level in the reservoir (16) rises, the oil flows into the cavity (51) through the second opening (55), and the volume of the resonance chamber (R) decreases. When the volume of the resonance chamber (R) decreases, the resonance frequency of the muffler (50) increases. In contrast, when the oil level in the reservoir (16) lowers, the oil flows out of the cavity (51) through the second opening (55), and the volume of the resonance chamber (R) increases. When the volume of the resonance chamber (R) increases, the resonance frequency of the muffler (50) decreases. In this manner, since the muffler (50) has the second opening (55), the oil flows in and out through the second opening (55), and the resonance frequency of the muffler (50) changes. Accordingly, noise with a wide range of resonance frequency can be reduced by the single muffler (50).

(2-2)

The first opening (53) of this embodiment is formed below the initial supply position (A1) which is a position of the oil surface in the reservoir (16) reached at the time of shipment, and communicates with the refrigerant space(S) when the oil level in the reservoir (16) lowers.

Since the first opening (53) is formed below the initial supply position (A1) which is a position of the oil surface reached at the time of shipment, the oil flows into the cavity (51) of the muffler (50) through the first opening (53) when the oil surface is at the initial supply position (A1). Then, when the position of the oil surface in the reservoir (16) lowers as the compressor operates, the first opening (53) communicates with the refrigerant space(S), whereby the cavity (51) of the muffler (50) communicates with the refrigerant space(S) and the muffler (50) serves a silencing function. Accordingly, noise with a low frequency that is produced as the oil level in the reservoir (16) lowers can be reduced.

(2-3)

The muffler (50) of this embodiment has the second communication passage (54) communicating with the cavity (51). The second opening (55) is formed at the end portion of the second communication passage (54).

Since the second opening (55) is formed at the end portion of the second communication passage (54), the position of the second opening can be adjusted by the position of the second communication passage (54). Accordingly, the level at which the oil flows in and out can be adjusted, and thus the volume of the resonance chamber (R) can be adjusted.

(3) Variations

(3-1) First Variation

In the compressor (100) of this embodiment, the second opening (55) only has to be formed below the first opening (53). Thus, the grooves constituting the first communication passage (52) and the second communication passage (54) may be formed on any of the lower end surface of the first end plate portion (45a) of the front head (45), the upper end surface of the cylinder (41), the lower end surface of the rear head (46), and the upper end surface of the second end plate portion (46a) of the rear head (46).

(3-2) Second Variation

As illustrated in FIG. 8, in the compressor (100) of this embodiment, the second opening (55) may be formed on the lower end surface of the rear head (46). In other words, in this variation, the muffler (50) does not have the second communication passage (54).

Here, the cavity (51) is formed across the front head (45), the cylinder (41), and the rear head (46). The rear head (46) is the lowermost one of the plurality of members constituting the compression mechanism (40). In this embodiment, the rear head (46) corresponds to a third member of the present disclosure.

The rear head (46) of this variation has a through hole (63) penetrating therethrough in the top-bottom direction (the axial direction). Internal spaces of the first recess (61) of the front head (45), the through hole (63) of the cylinder (41), and the through hole (63) of the rear head (46) constitute the cavity (51).

The second opening (55) is formed on the lower end surface of the rear head (46). In other words, the second opening (55) is formed on the lower surface of the compression mechanism (40). The second opening (55) is open toward the reservoir (16). The second opening (55) faces downward. The second opening (55) is formed below the first opening (53).

As illustrated in FIG. 8, if the oil level A in the reservoir (16) is above the second opening (55), the oil in the reservoir (16) flows into the cavity (51) through the second opening (55). The oil having flowed into the cavity (51) flows to the same level as that of oil in the reservoir (16). In this case, the bottom surface of the resonance chamber (R) in the cavity (51) consists of the oil surface. In this manner, the Helmholtz muffler (50) of this variation also serves a silencing function using the first communication passage (52) and the resonance chamber (R) that has the bottom surface consisting of the oil surface.

Since the second opening (55) is formed on the lower end surface of the rear head (46) which is the lowermost one of the plurality of members constituting the compression mechanism (40), the second opening (55) is also formed when the cavity (51) is formed in the compression mechanism (40). Accordingly, the second opening (55) can be formed easily.

FOURTH EMBODIMENT

A fourth embodiment will be described below. A compressor (100) of this embodiment has a muffler (50) different from that of the compressor (100) of the first embodiment. Here, the differences between the muffler (50) of this embodiment and the muffler (50) of the first embodiment will be described.

The muffler (50) of this embodiment includes a plurality of mufflers (50). In other words, the compression mechanism (40) of this embodiment includes the plurality of mufflers (50). The plurality of mufflers (50) are spaced at predetermined intervals in the circumferential direction so as to surround the drive shaft (30). In this embodiment, the compression mechanism (40) has two mufflers (50). The first muffler (50a) and the second muffler (50b) are disposed apart from each other by approximately 180°. The number of mufflers (50) described herein is merely one example.

As illustrated in FIGS. 9 and 10, each of the first muffler (50a) and the second muffler (50b) has the cavity (51), the first communication passage (52), and the first opening (53). The configurations of the cavity (51), the first communication passage (52), and the first opening (53) of the first muffler (50a) are the same as those of the muffler (50) of the first embodiment.

The cavity (51) of the second muffler (50b) is constituted by the internal spaces of the first recess (61) formed in the front head (45) and the second recess (62) formed in the cylinder (41). In this embodiment, the front head (45) and the cylinder (41) correspond to the first member of the present disclosure. The first recess (61) of the front head (45) and the second recess (62) of the cylinder (41) have the same diameter and are arranged coaxially. The first communication passage (52) of the second muffler (50b) is formed by the groove formed on the lower end surface of the first end plate portion (45a) of the front head (45) and the upper end surface of the cylinder (41). The first opening (53) of the second muffler (50b) is formed on the outer peripheral surface of the front head (45).

The first opening (53) of the first muffler (50a) is positioned below the first opening (53) of the second muffler (50b). The volume of the cavity (51) of the first muffler (50a) is larger than the volume of the cavity (51) of the second muffler (50b). In other words, the volume of the resonance chamber (R) of the first muffler (50a) is larger than the volume of the resonance chamber (R) of the second muffler (50b). Thus, the resonance frequency of the first muffler (50a) is lower than the resonance frequency of the second muffler (50b).

If as illustrated in FIG. 9, the oil level A in the reservoir (16) is below the first opening (53) of the first muffler (50a) (or if the oil level A in the reservoir (16) is low), resonance with a low frequency is generated in the casing (10). However, the first muffler (50a), whose resonance frequency is low, can muffle resonance with a low frequency generated in the casing (10). Accordingly, if the oil level in the reservoir (16) is low, noise produced by resonance in the casing (10) can be reduced by the first muffler (50a).

If as illustrated in FIG. 10, the oil level A in the reservoir (16) is above the first opening (53) of the first muffler (50a) and below the first opening (53) of the second muffler (50b) (or if the oil level A in the reservoir (16) is high), resonance with a high frequency is generated in the casing (10). In this case, the first muffler (50a) does not serve a silencing function because the oil flows into the cavity (51) through the first opening (53). On the other hand, since the first opening (53) of the second muffler (50b) is above the oil level A, the oil does not flow into the cavity (51), and the second muffler (50b) serves a silencing function. Specifically, the second muffler (50b), whose resonance frequency is high, can muffle resonance a high frequency generated in the casing (10). Accordingly, if the oil level in the reservoir (16) is high, noise produced by resonance in the casing (10) can be reduced by the second muffler (50b).

In this manner, the plurality of mufflers (50) provided in the compression mechanism (40) can cope with resonance frequency changing in the casing (10) as the oil level in the reservoir (16) changes. Accordingly, noise with a wide range of frequency that is produced in the casing (10) as the oil level changes can be reduced. The first muffler (50a) and the second muffler (50b) may have any of the structures of the first to third embodiments.

OTHER EMBODIMENTS

The above embodiments may be modified as follows.

In the compressor (100) of each embodiment, the cavity (51) of the muffler (50) is formed across the plurality of members constituting the compression mechanism (40), but may be formed in one single member.

In the compressor (100) of each embodiment, if the cavity (51) of the muffler (50) is formed across the plurality of members constituting the compression mechanism (40), the cavity (51) may be formed across any of the plurality of members constituting the compression mechanism (40). For example, the cavity (51) may be formed across the cylinder (41) and the rear head (46).

In the compressor (100) of each embodiment, the cavity (51) of the muffler (50) may be constituted only by the internal spaces of the recesses (61, 62) formed in any of the members constituting the compression mechanism (40). Specifically, for example, as illustrated in FIG. 9, the cavity (51) of the second muffler (50b) may be constituted by the first recess (61) recessed upward that is formed on the lower end surface of the first end plate portion (45a) of the front head (45) and the second recess (62) recessed downward that is formed on the upper end surface of the cylinder (41).

In the compressor (100) of each embodiment, the cavity (51) of the muffler (50) may be constituted only by the internal space of the through hole (63) formed in any of the members constituting the compression mechanism (40). Specifically, for example, as illustrated in FIG. 11, the cavity (51) may be formed by the through hole (63) penetrating the front head (45) in the top-bottom direction. If the through hole (63) constituting the cavity (51) is formed in the front head as illustrated in FIG. 11, the upper opening of the through hole (63) is closed by the cover member (47).

In the compressor (100) of each embodiment, the compression mechanism (40) may further include a cavity formation member constituting the cavity (51) of the muffler (50). In other words, the cavity (51) may be formed by a member other than the front head (45), the cylinder (41), and the rear head (46). The cavity formation member is, for example, a plate-shaped member and is disposed so as to cover part of the side surface of the front head (45). The cavity (51) is formed inside the cavity formation member. A through hole is formed on the side surface of the cavity formation member and constitutes the first opening (53).

The muffler (50) of each embodiment is applied to a one-cylinder rotary compressor but may be applied to a two-cylinder rotary compressor.

The muffler (50) of each embodiment may be applied to a compressor other than a rotary compressor.

While the embodiment and variations thereof have been described above, it will be understood that various changes in form and details may be made without departing from the spirit and scope of the claims. The embodiments, the variations, and the other embodiments may be combined and replaced with each other without deteriorating intended functions of the present disclosure.

The ordinal numbers such as “first,” “second,” “third,” . . . , described above are used to distinguish the terms to which these expressions are given, and do not limit the number and order of the terms.

As described above, the present disclosure is useful for a compressor and a refrigeration apparatus.

Claims

1. A compressor comprising: a casing having a bottom portion with a reservoir provided therein, the reservoir being configured to store oil;an electric motor housed in the casing;a compression mechanism disposed between the electric motor and the reservoir, the compression mechanism being configured to compress sucked gas refrigerant and to discharge the compressed gas refrigerant into the casing; anda resonance muffler provided in the compression mechanism,a refrigerant space being formed above the reservoir in the casing, the refrigerant space being configured so that the gas refrigerant discharged from the compression mechanism flows therethrough,the muffler including a cavity in which a resonance chamber is formed, anda first opening communicating with the resonance chamber and opening to the refrigerant space, andthe first opening being formed on a lower surface or an outer peripheral surface of the compression mechanism.

2. The compressor of claim 1, wherein the muffler further includes a first communication passage communicating with the resonance chamber, andthe first opening is formed at an end portion of the first communication passage.

3. The compressor of claim 1, wherein the compression mechanism includes a plurality of members arranged so as to overlap with each other,the plurality of members includes a first member,the first member includes a recess formed at an end surface of the first member in a direction in which the plurality of members overlap with each other, andan internal space of the recess forms part of the cavity.

4. The compressor of claim 1, wherein the compression mechanism includes a plurality of members arranged so as to overlap with each other,the plurality of members includes a second member,the second member includes a through hole penetrating the second member in a direction in which the plurality of members overlap with each other, andan internal space of the through hole forms part of the cavity.

5. The compressor of claim 1, wherein the compression mechanism includes a cylinder,a first closing member configured to cover an opening surface of one end of the cylinder in an axial direction, anda second closing member configured to cover an opening surface on an other end of the cylinder in the axial direction, andthe cavity is formed by at least one of the cylinder, the first closing member, and the second closing member.

6. The compressor of claim 1, wherein the muffler further includes a second opening, which communicates with the cavity and through which the oil flows in and out, andthe second opening is formed below the first opening.

7. The compressor of claim 6, wherein the first opening is formed below an initial supply position of an oil surface in the reservoir reached at a time of shipment, and the first opening communicates with the refrigerant space when an oil level in the reservoir lowers.

8. The compressor of claim 6, wherein the muffler further includes a second communication passage communicating with the cavity, andthe second opening is formed at an end portion of the second communication passage.

9. The compressor of claim 6, wherein the compression mechanism has a plurality of members overlapping with each other,the plurality of members includes a third member, which is a lowermost one of the plurality of members,the cavity is formed in the third member, andthe second opening is formed on a lower surface of the third member.

10. The compressor of claim 1, wherein the muffler includes a first muffler and a second muffler,the first opening of the first muffler is formed below the first opening of the second muffler, anda resonance frequency of the first muffler is lower than a resonance frequency of the second muffler.

11. A refrigeration apparatus including the compressor of claim 1.

12. The compressor of claim 2, wherein the compression mechanism includes a plurality of members arranged so as to overlap with each other,the plurality of members includes a first member,the first member includes a recess formed at an end surface of the first member in a direction in which the plurality of members overlap with each other, andan internal space of the recess forms part of the cavity.

13. The compressor of claim 2, wherein the compression mechanism includes a plurality of members arranged so as to overlap with each other,the plurality of members includes a second member,the second member includes a through hole penetrating the second member in a direction in which the plurality of members overlap with each other, andan internal space of the through hole forms part of the cavity.

14. The compressor of claim 3, wherein the compression mechanism includes a plurality of members arranged so as to overlap with each other,the plurality of members includes a second member,the second member includes a through hole penetrating the second member in a direction in which the plurality of members overlap with each other, andan internal space of the through hole forms part of the cavity.

15. The compressor of claim 2, wherein the compression mechanism includes a cylinder,a first closing member configured to cover an opening surface of one end of the cylinder in an axial direction, anda second closing member configured to cover an opening surface on an other end of the cylinder in the axial direction, andthe cavity is formed by at least one of the cylinder, the first closing member, and the second closing member.

16. The compressor of claim 3, wherein the compression mechanism includes a cylinder,a first closing member configured to cover an opening surface of one end of the cylinder in an axial direction, anda second closing member configured to cover an opening surface on an other end of the cylinder in the axial direction, andthe cavity is formed by at least one of the cylinder, the first closing member, and the second closing member.

17. The compressor of claim 4, wherein the compression mechanism includes a cylinder,a first closing member configured to cover an opening surface of one end of the cylinder in an axial direction, anda second closing member configured to cover an opening surface on an other end of the cylinder in the axial direction, andthe cavity is formed by at least one of the cylinder, the first closing member, and the second closing member.