Blow-by gas plate and reciprocating compressor

Abstract

A blow-by gas plate according to at least one embodiment of the present disclosure is a blow-by gas plate attachable to a casing of a reciprocating compressor, facing a recess provided in the casing as a part of a pressure equalization passage, so as to form the pressure equalization passage for returning blow-by gas of the reciprocating compressor to an intake side. The blow-by gas plate includes: one or more openings provided at positions facing the recess; and a mesh part provided in the opening and allowing the blow-by gas to pass therethrough.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a blow-by gas plate provided in a reciprocating compressor, and a reciprocating compressor including the blow-by gas plate.BACKGROUND

[0002] A reciprocating compressor converts rotational motion of a crankshaft (drive shaft) into reciprocating motion of a piston within a crank chamber, thereby compressing refrigerant gas circulating in a refrigeration cycle. The interior of the reciprocating compressor is partitioned into a suction chamber, a discharge chamber, a cylinder, and a crank chamber, and a lower part of the crank chamber serves as an oil sump for storing lubricating oil. The lubricating oil stored in the oil sump is supplied to each sliding part of the reciprocating compressor by a forced lubrication system using an oil pump.

[0003] Refrigerant gas circulating in the refrigeration cycle is drawn from the suction chamber through a suction valve into the cylinder by the reciprocating motion of the piston, compressed, and then discharged through a discharge valve to the discharge chamber.

[0004] Conventionally, in order to prevent the pressure inside the crank chamber from rising due to refrigerant gas (blow-by gas) leaking into the crank chamber through a gap between an inner wall surface of the cylinder and a piston ring, a pressure equalization path (balance hole) connecting the crank chamber and the suction chamber is provided to return the blow-by gas to the suction chamber.

[0005] The return of blow-by gas flowing into the suction chamber through the pressure equalization path to the suction chamber entrains oil droplets within the crank chamber, which may cause oil carry-over, where the amount of oil in the oil sump which stores lubricating oil decreases.

[0006] As a mechanism for preventing such oil carry-over, Patent Document 1, for example, discloses a reciprocating compressor including a partition member disposed between a crank chamber-side opening end of a pressure equalization path connecting the crank chamber to the suction chamber and a crankshaft to which a piston is connected, and further including an oil separator disposed between the partition member and the opening end of the pressure equalization path.

[0007] With the reciprocating compressor configured in this way, the partition member prevents oil droplets within the crank chamber from directly flowing into the opening end of the pressure equalization path, and furthermore, the oil separator reduces the amount of lubricating oil flowing into the opening end of the pressure equalization path, thus preventing oil carry-over, where the amount of oil in the oil sump decreases.Citation ListPatent Literature

[0008] Patent Document 1: WO2014 / 054092ASUMMARYProblems to be Solved

[0009] However, in contrast to the configuration of Patent Document 1, it is desired to prevent oil carry-over caused by returning blow-by gas to the suction chamber, without providing a partition member within the crank chamber and without providing an oil separator that protrudes into the crank chamber.

[0010] In view of the above circumstances, an object of at least one embodiment of the present disclosure is to provide a blow-by gas plate and a reciprocating compressor capable of reducing oil carry-over caused by returning blow-by gas to the suction chamber with a simple structure.Solution to the Problems

[0011] (1) A blow-by gas plate according to at least one embodiment of the present disclosure is a blow-by gas plate attachable to a casing of a reciprocating compressor, facing a recess provided in the casing as a part of a pressure equalization passage, so as to form the pressure equalization passage for returning blow-by gas of the reciprocating compressor to an intake side, the blow-by gas plate comprising: one or more openings provided at positions facing the recess; and a mesh part provided in the opening and allowing the blow-by gas to pass therethrough. (2) A reciprocating compressor according to at least one embodiment of the present disclosure comprises: the blow-by gas plate having the above configuration (1); a housing in which a suction chamber, a discharge chamber, a cylinder, and a crank chamber are provided, a lower part of the crank chamber being configured as an oil sump for storing lubricating oil; a piston reciprocably disposed within the cylinder; a crankshaft rotatably disposed in the crank chamber and connected to the piston via a connecting rod; and a bearing housing in which a bearing part for bearing the crankshaft is disposed, wherein the recess is formed in the bearing housing. Advantageous Effects

[0012] According to at least one embodiment of the present disclosure, it is possible to reduce oil carry-over caused by returning blow-by gas to the suction chamber with a simple structure.BRIEF DESCRIPTION OF DRAWINGS

[0013] FIG. 1 is a diagram illustrating a schematic longitudinal cross-section of a reciprocating compressor according to the present embodiment, together with a refrigeration cycle. FIG. 2 is a diagram illustrating a schematic transverse cross-section of the reciprocating compressor according to the present embodiment. FIG. 3 is a perspective cross-sectional view illustrating the reciprocating compressor according to the present embodiment. FIG. 4 is a view of a bearing housing and a partition plate as seen from the inside to the outside of a crank chamber. FIG. 5 is a view of the bearing housing as seen from the inside to the outside of the crank chamber. FIG. 6 is a schematic cross-sectional view taken along the line VI-VI in FIG. 5. DETAILED DESCRIPTION

[0014] Embodiments of the present disclosure will be described below with reference to the accompanying drawings. It is intended, however, that unless particularly identified, dimensions, materials, shapes, relative positions, and the like of components described in the embodiments shall be interpreted as illustrative only and not intended to limit the scope of the present disclosure.

[0015] For instance, an expression of relative or absolute arrangement such as "in a direction", "along a direction", "parallel", "orthogonal", "centered", "concentric" and "coaxial" shall not be construed as indicating only the arrangement in a strict literal sense, but also includes a state where the arrangement is relatively displaced by a tolerance, or by an angle or a distance whereby it is possible to achieve the same function.

[0016] For instance, an expression of an equal state such as "same" "equal" and "uniform" shall not be construed as indicating only the state in which the feature is strictly equal, but also includes a state in which there is a tolerance or a difference that can still achieve the same function.

[0017] Further, for instance, an expression of a shape such as a rectangular shape or a cylindrical shape shall not be construed as only the geometrically strict shape, but also includes a shape with unevenness or chamfered corners within the range in which the same effect can be achieved.

[0018] On the other hand, an expression such as "comprise", "include", "have", "contain" and "constitute" are not intended to be exclusive of other components.

[0019] Embodiments of the present invention will be described below with reference to FIGs. 1 to 6. In the description of the drawings, the same elements are denoted by the same reference numerals and not described in detail. The dimensional ratios in the drawings are exaggerated for convenience of explanation and may differ from the actual ratios.

[0020] FIG. 1 is a diagram illustrating a schematic longitudinal cross-section of a reciprocating compressor 1 according to the present embodiment, together with a refrigeration cycle. FIG. 2 is a diagram illustrating a schematic transverse cross-section of the reciprocating compressor 1 according to the present embodiment. FIG. 3 is a perspective cross-sectional view illustrating the reciprocating compressor 1 according to the present embodiment. FIG. 4 is a view of a bearing housing 60 and a partition plate 70 as seen from the inside to the outside of a crank chamber 34. FIG. 5 is a view of the bearing housing 60 as seen from the inside to the outside of the crank chamber 34. FIG. 6 is a schematic cross-sectional view taken along the line VI-VI in FIG. 5. In FIG. 5, openings 71 and a lubricating oil discharge hole 74 of the partition plate 70 are indicated by dashed-two dotted lines for easy understanding.

[0021] First, the configuration of the refrigeration cycle will be described with reference to FIG. 1.

[0022] The refrigeration cycle has an annular refrigerant circulation path 10 through which refrigerant circulates, and the refrigerant circulation path 10 is provided with a reciprocating compressor 1, a condenser (high-pressure-side heat exchanger) 12, an expansion valve (expander) 14, and an evaporator (low-pressure-side heat exchanger) 16, which are connected in this order in the refrigerant circulation direction. In this embodiment, the refrigerant circulation path 10 is further provided with an oil separator 18 and a receiver 20.

[0023] In the refrigeration cycle, the reciprocating compressor 1 is configured, for example, to suck and compress refrigerant at a pressure (suction pressure) of 0.1 MPa to 0.3 MPa, and to discharge refrigerant at a pressure (discharge pressure) of 1.5 MPa to 2 MPa, but the ranges of the suction pressure and the discharge pressure of the refrigerant are not limited thereto. The refrigerant is, for example, various alternative chlorofluorocarbon refrigerants such as R32, or ammonia, carbon dioxide, or the like.

[0024] Next, a configuration of the reciprocating compressor 1 according to the present embodiment will be described with reference to FIGs. 1 to 6.

[0025] The reciprocating compressor 1 generally includes: a housing 22; a piston 36 reciprocably disposed within a cylinder 32; a crankshaft 40 rotatably disposed in a crank chamber 34; a bearing part 50A on an oil pump 90 side for bearing the crankshaft 40 and a bearing part 50B on one end side (the right side in FIG. 1) of the crankshaft 40; a bearing housing 60 in which the bearing part 50A on the oil pump 90 side is disposed; a partition plate 70 provided between the bearing housing 60 and the crank chamber 34 and forming a closed space V together with the bearing housing 60; and a pressure equalization path 80 that connects the closed space V and the suction chamber 28. Each configuration will be described below. For convenience of description, the circumferential direction centered on the rotational central axis AX of the crankshaft 40 is defined as circumferential direction C, the extending direction of the rotational central axis AX is defined as axial direction X, and the radial direction centered on the rotational central axis AX is defined as radial direction R. Further, the vertical direction is assumed to coincide with the upper-lower direction on the paper in each drawing.

[0026] As shown in FIG. 1, the housing 22 is provided with a suction port 24 and a discharge port 26. The suction port 24 is connected to the outlet of the evaporator 16 via piping, and the discharge port 26 is connected to the inlet of the oil separator 18 via piping.

[0027] As shown in FIGs. 1 to 3, inside the housing 22, a suction chamber 28, a discharge chamber 30, a cylinder 32, a crank chamber 34, and an oil sump 35 are provided. A piston 36 is reciprocably disposed within the cylinder 32, and a compression chamber W is defined within the cylinder 32 by the piston 36. The suction chamber 28 communicates with the suction port 24, and is communicable with the compression chamber W via a suction valve. The discharge chamber 30 communicates with the discharge port 26, and is communicable with the compression chamber W via a discharge valve.

[0028] The lower end of the cylinder 32 communicates with the crank chamber 34, and a connecting rod 38 connected to the piston 36 extends into the crank chamber 34. A crankshaft 40 is rotatably disposed in the crank chamber 34, and the connecting rod 38 is connected to the crankshaft 40.

[0029] The oil sump 35 is formed at a bottom portion of the crank chamber 34, as shown in FIG. 1. Oil stored in the oil sump 35 is supplied as lubricating oil to each sliding part during operation of the reciprocating compressor 1. In the present embodiment, oil filters 46 and 48 for purifying the lubricating oil are installed respectively inside the oil sump 35 and outside the housing 22.

[0030] One end side (the right side in FIG. 1) of the crankshaft 40 airtightly penetrates the housing 22 via a shaft seal 43, and a drive source (not shown) is connected to the outer end of the crankshaft 40. When the crankshaft 40 is rotated by the drive source, the piston 36 reciprocates within the cylinder 32, whereby a suction stroke, a compression stroke, and a discharge stroke of the refrigerant are repeatedly executed.

[0031] The bearing part 50A is configured to bear the crankshaft 40 on the oil pump 90 side opposite to the drive source, as shown in FIG. 3. The inner periphery of the bearing part 50A has a groove portion 51 so that lubricating oil from the oil sump 35 contacts the outer periphery of the crankshaft 40, as shown in FIG. 3. One end side (the front side in FIG. 3) of the bearing part 50A has a flange shape and is configured to abut on the bearing housing 60.

[0032] In the bearing housing 60, as shown in FIG. 3, the bearing part 50A is disposed. The bearing housing 60 is fixed to the housing 22 by a fixing part (not shown). The fixing part is not particularly limited, but is, for example, a bolt.

[0033] In the reciprocating compressor 1 according to the present embodiment, the housing 22 and the bearing housing 60 are included in a casing 2 of the reciprocating compressor 1 that forms the crank chamber 34 and the oil sump 35. In other words, the housing 22 and the bearing housing 60 are components of the casing 2 of the reciprocating compressor 1 according to the present embodiment.

[0034] In the bearing housing 60, as shown in FIG. 3, an oil path 61 through which lubricating oil passes is formed toward the radially outer side. Further, the bearing housing 60 has a recess 62 on one end side (the front side in FIG. 3), which is recessed in the axial direction of the crankshaft 40. The recess 62 forms a closed space V when the partition plate 70 is fixed to the bearing housing 60. The closed space V includes a first closed space V1 connected to the pressure equalization path 80 and a second closed space V2 connected to the oil path 61. Lubricating oil supplied from the oil sump 35 to the bearing housing 60 flows into the second closed space V2 via the oil path 61.

[0035] The recess 62 extends in the circumferential direction C so as to surround the bearing part 50A in the circumferential direction C in a radially outer region of the bearing part 50A. The recess 62 includes a first recess 621 forming the first closed space V1 and a second recess 622 forming the second closed space V2. The first recess 621 and the second recess 622 are separated by wall portions 623 and 624. That is, when the partition plate 70 is fixed to the bearing housing 60, the first closed space V1 is separated from the second closed space V2.

[0036] The first recess 621 and the second recess 622 each have a partially annular shape when viewed along the axial direction X from the inside to the outside of the crank chamber 34.

[0037] The second recess 622 is provided below the first recess 621.

[0038] In the recess 62, a plurality of protrusions extending in the radial direction R within the recess 62 and protruding along the axial direction X from the outside to the inside of the crank chamber 34, that is, toward the partition plate 70 described later, are formed as ribs 66 for reinforcing the strength of the bearing housing 60.

[0039] The ribs 66 have a protruding height in the axial direction X from a bottom surface 62a of the recess 62 that is lower than that of the wall portions 623 and 624. Therefore, when the partition plate 70 described later is fixed to the bearing housing 60, the partition plate 70 comes into close contact with top portions 623a and 624a of the wall portions 623 and 624 facing in the axial direction X, but is separated in the axial direction X from a top portion 66a of the rib 66 facing in the axial direction X.

[0040] The partition plate 70 is provided between the bearing housing 60 and the crank chamber 34, as shown in FIG. 3. Further, the partition plate 70 is fixed to the bearing housing 60 so as to cover the recess 62 of the bearing housing 60. The means for fixing the partition plate 70 to the bearing housing 60 is not particularly limited, but is, for example, fastening by bolts. That is, the partition plate 70 is disposed on the inner side of the crank chamber 34 along the axial direction X with respect to the recess 62.

[0041] The partition plate 70 has an opening 71 connecting the crank chamber 34 and the first closed space V1, as shown in FIGs. 3 and 4. Further, the partition plate 70 has a lubricating oil discharge hole 74 connecting the crank chamber 34 and the second closed space V2.

[0042] As shown in FIGs. 3 and 4, a plurality of the openings 71 are formed at intervals in the circumferential direction C so as to communicate with the first closed space V1 communicating with the pressure equalization path 80. Each opening 71 is provided at a position facing the recess 62 (first closed space V1) in the axial direction X.

[0043] The lubricating oil discharge hole 74 is formed so as to communicate with the second closed space V2 communicating with the oil path 61 of the bearing housing 60, as shown in FIG. 3. The lubricating oil discharge hole 74 is formed by a flat cutout portion having a wide opening shape, as shown in FIG. 3.

[0044] Each opening 71 is provided with a mesh part 72. The mesh part 72 is a net member provided so as to cover each opening 71. The opening size of the mesh part 72 is preferably defined such that blow-by gas can pass therethrough, and oil droplets of lubricating oil cannot pass therethrough or have difficulty passing therethrough.

[0045] The partition plate 70 includes a non-opening region 73 where the opening 71 is not provided between two adjacent openings 71 in the circumferential direction C. In the reciprocating compressor 1 according to the present embodiment, the partition plate 70 includes a plurality of non-opening regions 73. At least one of the plurality of non-opening regions 73 is provided at a position facing the rib 66 in the axial direction X when the partition plate 70 is attached to the bearing housing 60.

[0046] The pressure equalization path 80 is provided to suppress an increase in pressure in the crank chamber 34 due to blow-by gas leaking through a gap between the piston 36 and the wall surface of the cylinder 32 during operation of the reciprocating compressor 1.

[0047] The pressure equalization path 80 has an opening end (inlet end) 81 opening to the first closed space V1 and an opening end (outlet end) 82 opening to the suction chamber 28 (see FIG. 3).

[0048] That is, in the reciprocating compressor 1 according to the present embodiment, a pressure equalization passage 100 for returning blow-by gas of the reciprocating compressor 1 to the intake side (specifically, the suction chamber 28) is formed by the recess 62 forming the first closed space V1, the partition plate 70, and the pressure equalization path 80.

[0049] Next, effects of the reciprocating compressor 1 according to the present embodiment will be described.

[0050] For example, in the case of a reciprocating compressor not provided with the partition plate 70, during operation of the reciprocating compressor, oil droplets of lubricating oil after lubricating bearings or the like are scattered from the crankshaft or the bearings, and the lubricating oil is entrained by the blow-by gas flowing into the suction chamber through the pressure equalization path, which may cause a decrease in oil amount in the oil sump, resulting in oil carry-over.

[0051] In contrast, with the reciprocating compressor 1 according to the present embodiment, since the partition plate 70 is provided between the bearing housing 60 and the crank chamber 34, lubricating oil attempting to be entrained by the blow-by gas passing through the mesh part 72 covering each opening 71 has difficulty passing through the mesh part 72 and is returned to the oil sump 35. Furthermore, even if lubricating oil entrained by the blow-by gas slightly passes through the mesh part 72, while passing through the first closed space V1, the entrained oil droplets become larger and are separated from the blow-by gas by gravitational sedimentation. The oil droplets separated from the blow-by gas are returned to the oil sump 35 from a lower part of the first closed space V1 via the opening 71 and the mesh part 72. On the other hand, the blow-by gas from which the oil droplets have been separated moves from the first closed space V1 to the suction chamber 28 via the pressure equalization path 80. Therefore, the amount of lubricating oil flowing into the suction chamber 28 through the pressure equalization path 80 is reduced, and oil carry-over of the reciprocating compressor 1 can be prevented.

[0052] In the reciprocating compressor 1 according to the present embodiment, by providing the mesh part 72 in the opening 71, the area of the opening 71 can be made relatively large to reduce the flow velocity of the blow-by gas entering the first recess 621, and oil droplet entrainment force of the blow-by gas can be reduced, thus reducing the amount of oil droplets entering the first recess 621. Further, with the reciprocating compressor 1 according to the present embodiment, the entry of oil droplets into the first recess 621 can be inhibited by the mesh part 72, thus reducing the amount of oil droplets entering the first recess 621. As a result, it is possible to reduce oil carry-over.

[0053] In the reciprocating compressor 1 according to the present embodiment, the first recess 621 forming the first closed space V1 is formed in an annular shape with one end portion 621a and the other end portion 621b in the circumferential direction C facing downward (positioned lower than other portions). The opening 71 is formed to include a position facing, in the axial direction X, at least one of the one end portion 621a and the other end portion 621b. In the example shown in FIG. 5, the opening 71 is formed to include positions facing, in the axial direction X, the one end portion 621a and the other end portion 621b.

[0054] For example, as shown in FIG. 6, at at least one of the end portions 621a and 621b, a wall surface 621c defining the first recess 621 and facing in the circumferential direction C is inclined downward from the bottom surface 62a of the first recess 621 toward the partition plate 70. FIG. 6 shows the vicinity of the one end portion 621a.

[0055] This makes it easier for lubricating oil accumulated in the first recess 621 along the wall surface 621c to return to the crank chamber 34 through the opening 71 and the mesh part 72, thus reducing oil carry-over.

[0056] In the reciprocating compressor 1 according to the present embodiment, a plurality of the openings 71 are provided at intervals in the circumferential direction C at positions facing, in the axial direction X, the recess 62 formed in an annular shape, when the partition plate 70 is attached to the casing 2 (bearing housing 60).

[0057] By providing the openings 71 divided in the circumferential direction C, the length of each opening 71 in the circumferential direction C is shortened. This shortens the extension length of the mesh part 72 in the circumferential direction C and improves the rigidity of the mesh part 72. Therefore, even if an external force acts on the mesh part 72 due to the blow-by gas passing through the mesh part 72 when flowing into the first recess 621, deformation or the like of the mesh part 72 can be suppressed.

[0058] The first closed space V1 in the bearing housing 60 is shaped to have a relatively large flow path cross-sectional area, reducing the flow velocity of the blow-by gas returning to the suction chamber 28 to further promote gravitational sedimentation of oil droplets. Further, a plurality of the above-described ribs 66 are provided in the space formed by the recess 62 in the bearing housing 60. Then, at least one of the non-opening regions 73 is provided at a position facing the rib 66 in the axial direction X when the partition plate 70 is attached to the casing 2 (bearing housing 60).

[0059] By providing the ribs 66 in this manner, the blow-by gas passes through a complex flow path, further promoting oil separation. That is, when the blow-by gas and oil droplets flow through the recess 62 in the circumferential direction C, the ribs 66 and the non-opening regions 73 can function like a throttle to cause pressure loss, reducing the flow velocity of the blow-by gas and oil droplets within the recess 62, reducing the amount of oil droplets carried away from the recess 62 together with the blow-by gas. Further, it can be expected that the blow-by gas and oil droplets flowing in the circumferential direction C between the ribs 66 and the non-opening regions 73 form a vortex flow on the downstream side of the throttle formed by the ribs 66 and the non-opening regions 73 facing them in the axial direction X, thereby promoting coalescence of oil droplets and causing the oil droplets to become larger. This is expected to reduce the amount of oil droplets carried away from the recess 62 together with the blow-by gas.

[0060] In the reciprocating compressor 1 according to the present embodiment, the partition plate 70 may include at least one non-opening region 73 where the opening 71 is not provided between two adjacent openings 71 in the circumferential direction C. At least one of the non-opening regions 73 may be provided at a position facing, in the axial direction X, the opening end 81 of the pressure equalization path 80 opening to the first recess 621, when the partition plate 70 is attached to the casing 2 (bearing housing 60). In other words, at least one of the non-opening regions 73 may be provided at a position overlapping the opening end 81 in the circumferential direction C when viewed from the axial direction X.

[0061] This allows fewer oil droplets to be carried away with the blow-by gas from the opening end 81 opening to the first recess 621, compared to the case where the opening 71 is provided at a position facing, in the axial direction X, the opening end 81 opening to the first recess 621.

[0062] The present disclosure is not limited to the embodiments described above, but includes modifications to the embodiments described above, and embodiments composed of combinations of those embodiments.

[0063] For example, in the above-described embodiments, the partition plate 70 has the lubricating oil discharge hole 74, but does not have to have the lubricating oil discharge hole 74.

[0064] Further, in the above-described embodiments, the recess 62 is provided in the bearing housing 60, but may be provided in the housing 22. That is, the recess 62 only needs to be provided in the casing 2. The partition plate 70 only needs to be fixed to the casing 2 so as to cover the recess 62.

[0065] The contents described in the above embodiments would be understood as follows, for instance. (1) A blow-by gas plate (partition plate 70) according to at least one embodiment of the present disclosure is a blow-by gas plate (partition plate 70) attachable to a casing 2 of a reciprocating compressor 1, facing a recess 62 (first recess 621) provided in the casing 2 as a part of a pressure equalization passage 100, so as to form the pressure equalization passage 100 for returning blow-by gas of the reciprocating compressor 1 to an intake side. The blow-by gas plate (partition plate 70) according to at least one embodiment of the present disclosure includes: one or more openings 71 provided at positions facing the recess 62; and a mesh part 72 provided in the opening 71 and allowing the blow-by gas to pass therethrough.

[0066] With the above configuration (1), by providing the mesh part 72 in the opening 71, the area of the opening 71 can be made relatively large to reduce the flow velocity of the blow-by gas entering the recess 62 (pressure equalization passage 100), and oil droplet entrainment force of the blow-by gas can be reduced, thus reducing the amount of oil droplets entering the recess 62 (pressure equalization passage 100). Further, with the above configuration (1), the entry of oil droplets into the recess 62 (pressure equalization passage 100) can be inhibited by the mesh part 72, thus reducing the amount of oil droplets entering the recess 62 (pressure equalization passage 100). As a result, it is possible to reduce oil carry-over.

[0067] (2) In some embodiments, in the above configuration (1), the opening 71 may be formed to include a position facing at least one of one end portion 621a and the other end portion 621b of the recess 62 in circumferential direction C, the recess 62 being formed in an annular shape with the one end portion 621a and the other end portion 621b facing downward, when the blow-by gas plate (partition plate 70) is attached to the casing 2. The mesh part 72 may be provided in the opening 71 so as to cover the at least one of the one end portion 621a and the other end portion 621b, when the blow-by gas plate (partition plate 70) is attached to the casing 2.

[0068] With the above configuration (2), lubricating oil accumulated in the recess 62 (pressure equalization passage 100) is facilitated to return to the outside of the recess 62 (pressure equalization passage 100) through the opening 71 and the mesh part 72, thus reducing oil carry-over.

[0069] (3) In some embodiments, in the above configuration (1) or (2), a plurality of the openings 71 may be provided at intervals in circumferential direction C at positions facing the recess 62 formed in an annular shape, when the blow-by gas plate (partition plate 70) is attached to the casing 2.

[0070] With the above configuration (3), by providing the openings 71 divided in the circumferential direction C, the length of each opening 71 in the circumferential direction C is shortened. This shortens the extension length of the mesh part 72 in the circumferential direction C and improves the rigidity of the mesh part 72. Therefore, even if an external force acts on the mesh part 72 due to the blow-by gas passing through the mesh part 72 when flowing into the recess 62 (pressure equalization passage 100), deformation or the like of the mesh part 72 can be suppressed.

[0071] (4) In some embodiments, in the above configuration (3), the blow-by gas plate (partition plate 70) may include at least one non-opening region 73 where the opening 71 is not provided between two adjacent openings 71 in the circumferential direction C. At least one of the at least one non-opening region 73 may be provided at a position facing a protrusion (rib 66) that is provided within the recess 62 and protrudes toward the blow-by gas plate (partition plate 70), when the blow-by gas plate (partition plate 70) is attached to the casing 2.

[0072] With the above configuration (4), when the blow-by gas and oil droplets flow through the recess 62 (pressure equalization passage 100) in the circumferential direction C, the protrusion (rib 66) and the non-opening region 73 can function like a throttle to cause pressure loss, reducing the flow velocity of the blow-by gas and oil droplets within the recess 62 (pressure equalization passage 100), reducing the amount of oil droplets carried away from the recess 62 (pressure equalization passage 100) together with the blow-by gas. Further, it can be expected that the blow-by gas and oil droplets flowing in the circumferential direction C between the protrusion (rib 66) and the non-opening region 73 form a vortex flow on the downstream side of the throttle formed by the protrusion (rib 66) and the non-opening region 73 facing it, thereby promoting coalescence of oil droplets and causing the oil droplets to become larger. This is expected to reduce the amount of oil droplets carried away from the recess 62 (pressure equalization passage 100) together with the blow-by gas.

[0073] (5) In some embodiments, in the above configuration (3) or (4), the blow-by gas plate (partition plate 70) may include at least one non-opening region 73 where the opening 71 is not provided between two adjacent openings 71 in the circumferential direction C. At least one of the at least one non-opening region 73 may be provided at a position facing, in the axial direction X, an opening end 81 that opens to the recess 62, when the blow-by gas plate (partition plate 70) is attached to the casing 2.

[0074] With the above configuration (5), fewer oil droplets are carried away with the blow-by gas from the opening end 81 opening to the recess 62, compared to the case where the opening 71 is provided at a position facing, in the axial direction X, the opening end 81 opening to the recess 62.

[0075] (6) A reciprocating compressor 1 according to at least one embodiment of the present disclosure includes: the blow-by gas plate (partition plate 70) according to any one of (1) to (5) above. The reciprocating compressor 1 according to at least one embodiment of the present disclosure includes a housing 22 in which a suction chamber 28, a discharge chamber 30, a cylinder 32, and a crank chamber 34 are provided, a lower part of the crank chamber 34 being configured as an oil sump 35 for storing lubricating oil. The reciprocating compressor 1 according to at least one embodiment of the present disclosure includes a piston 36 reciprocably disposed within the cylinder 32; a crankshaft 40 rotatably disposed in the crank chamber 34 and connected to the piston 36 via a connecting rod 38; and a bearing housing 60 in which a bearing part 50A for bearing the crankshaft 40 is disposed. The recess 62 is formed in the bearing housing 60.

[0076] With the above configuration (6), by providing the mesh part 72 in the opening 71, the area of the opening 71 can be made relatively large to reduce the flow velocity of the blow-by gas entering the recess 62 (pressure equalization passage 100), and oil droplet entrainment force of the blow-by gas can be reduced, thus reducing the amount of oil droplets entering the recess 62 (pressure equalization passage 100). Further, with the above configuration (6), the entry of oil droplets into the recess 62 (pressure equalization passage 100) can be inhibited by the mesh part 72, thus reducing the amount of oil droplets entering the recess 62 (pressure equalization passage 100). As a result, it is possible to reduce oil carry-over.

[0077] (7) In some embodiments, in the above configuration (6), the recess 62 may be formed in an annular shape with one end portion 621a and the other end portion 621b in circumferential direction C facing downward. The opening 71 may be formed to include a position facing at least one of the one end portion 621a and the other end portion 621b of the recess 62. At the at least one of the one end portion 621a and the other end portion 621b, a wall surface 621c defining the recess 62 and facing in the circumferential direction C may be inclined downward from a bottom surface 62a of the recess 62 toward the opening 71.

[0078] With the above configuration (7), lubricating oil accumulated in the recess 62 (pressure equalization passage 100) along the wall surface 621c is facilitated to return to the crank chamber 34 through the opening 71 and the mesh part 72, thus reducing oil carry-over.Reference Signs List

[0079] 1Reciprocating compressor 2Casing 22Housing 24Suction port 26Discharge port 28Suction chamber 30Discharge chamber 32Cylinder 34Crank chamber 35Oil sump 36Piston 38Connecting rod 40Crankshaft 50ABearing part 60Bearing housing 62Recess 62aBottom surface 66Rib 66aTop portion 70Partition plate 71Opening 72Mesh part 73Non-opening region 74Lubricating oil discharge hole 80Pressure equalization path 81Opening end (Inlet end) 82Opening end (Outlet end) 100Pressure equalization passage 621First recess 621aEnd portion 621bEnd portion 621cWall surface 622Second recess 623Wall portion 623aTop portion 624Wall portion 624aTop portion

Claims

1. A blow-by gas plate attachable to a casing of a reciprocating compressor, facing a recess provided in the casing as a part of a pressure equalization passage, so as to form the pressure equalization passage for returning blow-by gas of the reciprocating compressor to an intake side, the blow-by gas plate comprising: one or more openings provided at positions facing the recess; and a mesh part provided in the opening and allowing the blow-by gas to pass therethrough.

2. The blow-by gas plate according to claim 1, wherein the opening is formed to include a position facing at least one of one end portion and the other end portion of the recess in a circumferential direction, the recess being formed in an annular shape with the one end portion and the other end portion facing downward, when the blow-by gas plate is attached to the casing, and the mesh part is provided in the opening so as to cover the at least one of the one end portion and the other end portion, when the blow-by gas plate is attached to the casing.

3. The blow-by gas plate according to claim 1 or 2, wherein a plurality of the openings are provided at intervals in a circumferential direction at positions facing the recess formed in an annular shape, when the blow-by gas plate is attached to the casing.

4. The blow-by gas plate according to claim 3, comprising at least one non-opening region where the opening is not provided between two adjacent openings in the circumferential direction, wherein at least one of the at least one non-opening region is provided at a position facing a protrusion that is provided within the recess and protrudes toward the blow-by gas plate, when the blow-by gas plate is attached to the casing.

5. The blow-by gas plate according to claim 3, comprising at least one non-opening region where the opening is not provided between two adjacent openings in the circumferential direction, wherein at least one of the at least one non-opening region is provided at a position facing, in an axial direction, an opening end that opens to the recess, when the blow-by gas plate is attached to the casing.

6. A reciprocating compressor, comprising: the blow-by gas plate according to claim 1 or 2; a housing in which a suction chamber, a discharge chamber, a cylinder, and a crank chamber are provided, a lower part of the crank chamber being configured as an oil sump for storing lubricating oil; a piston reciprocably disposed within the cylinder; a crankshaft rotatably disposed in the crank chamber and connected to the piston via a connecting rod; and a bearing housing in which a bearing part for bearing the crankshaft is disposed, wherein the recess is formed in the bearing housing.

7. The reciprocating compressor according to claim 6, wherein the recess is formed in an annular shape with one end portion and the other end portion in a circumferential direction facing downward, the opening is formed to include a position facing at least one of the one end portion and the other end portion of the recess, and at the at least one of the one end portion and the other end portion, a wall surface defining the recess and facing in the circumferential direction is inclined downward from a bottom surface of the recess toward the opening.

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