Hermetic compressor

Abstract

This hermetic compressor comprises: a hermetic container in which an oil reservoir for storing refrigerating machine oil is formed; a compression mechanism unit that is arranged in the hermetic container and compresses a refrigerant; an electric motor unit that is arranged in the hermetic container above the compression mechanism unit and drives the compression mechanism unit; a main shaft that transmits the rotational force of the electric motor unit to the compression mechanism unit; and a bearing unit that rotatably supports the main shaft below the electric motor unit. In the hermetic compressor, oil in the oil reservoir is supplied to the bearing unit through an oil supply hole formed in the main shaft. The hermetic compressor includes a hollow cover that is fixed to the electric motor unit and arranged concentrically with respect to the main shaft between the electric motor unit and the compression mechanism unit, and into which the refrigerating machine oil that lubricated the bearing unit flows, the cover having a conical shape with a diameter increasing from top to bottom.

Description

Technical Field

[0001] The present disclosure relates to a hermetic compressor mounted on an air conditioner or the like.

Background Art

[0002] A conventional hermetic compressor includes a motor unit having a stator and a rotor in a hermetic container formed with an oil sump at the bottom, and a compression mechanism unit connected below the motor unit via a main shaft and compressing a refrigerant by the rotation of the main shaft. The refrigerant compressed by the compression mechanism unit is discharged from the compression mechanism unit into the hermetic container and then discharged out of the hermetic container through a discharge pipe. In this type of hermetic compressor, the refrigerant oil in the oil sump is supplied to a bearing that rotatably supports the main shaft to lubricate the bearing, and the lubricated refrigerant oil is discharged out of the bearing from the end of the bearing. In the hermetic compressor, the refrigerant oil discharged from the end of the bearing is entrained in the refrigerant gas flowing in the hermetic container and flows out of the hermetic container together with the refrigerant gas, and there is a risk that the refrigerant oil lubricating the inside of the hermetic compressor will run out.

[0003] On the other hand, there is a hermetic compressor in which a cylindrical cover is fixed to the lower end face of the rotor of the motor unit (see, for example, Patent Document 1). In the hermetic compressor of Patent Document 1, the cover is arranged concentrically with the main shaft at a height position that encloses the end of the bearing. In the hermetic compressor of Patent Document 1, the refrigerant oil discharged from the end of the bearing is received by the inner wall surface of the cover, and the refrigerant oil adhering to the inner wall surface is flung to the outside of the cover by centrifugal force from the lower end of the cover, and the flung refrigerant oil is returned to the oil sump.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the hermetic compressor of Patent Document 1, the cover is cylindrical, and the inner wall surface of the cover is a vertical surface extending in the axial direction. Therefore, mainly radial centrifugal force acts on the refrigerating machine oil adhering to the inner wall surface of the cover, and only its own weight acts in the gravitational direction. That is, in the hermetic compressor of Patent Document 1, when the refrigerating machine oil adhering to the inner wall surface of the cover is flung out of the cover from the lower end portion of the cover, the force acting thereon is mostly the radial centrifugal force, and the force in the gravitational direction is small. For this reason, the refrigerating machine oil flung out of the cover from the lower end portion of the cover is easily lifted by a slight swirling flow of the refrigerant gas flowing in the sealed container and is discharged out of the hermetic compressor together with the refrigerant gas flow.

[0006] The present disclosure has been made in view of such points, and an object thereof is to provide a hermetic compressor capable of suppressing the refrigerating machine oil flung out of the cover from the lower end portion of the cover from being lifted by the refrigerant gas flow and discharged out of the hermetic compressor.

Means for Solving the Problems

[0007] The hermetic compressor according to the present disclosure includes a sealed container in which an oil reservoir portion for storing refrigerating machine oil is formed, a compression mechanism portion disposed in the sealed container for compressing a refrigerant, an electric motor portion disposed above the compression mechanism portion in the sealed container for driving the compression mechanism portion, a main shaft for transmitting the rotational force of the electric motor portion to the compression mechanism portion, and a bearing portion for rotatably supporting the main shaft below the electric motor portion, and is a hermetic compressor in which the oil in the oil reservoir portion is supplied to the bearing portion through an oil supply hole formed in the main shaft, and includes a hollow cover fixed to the electric motor portion and disposed concentrically with respect to the main shaft between the electric motor portion and the compression mechanism portion, into which the refrigerating machine oil lubricating the bearing portion flows A discharge muffler that is disposed between the compression mechanism section and the electric motor section, has a plate-shaped upper wall portion having a through-hole through which a bearing portion passes, and a side wall portion extending downward from the outer peripheral edge of the upper wall portion, and covers a space where the refrigerant compressed by the compression mechanism section is discharged; and the cover is conical with a diameter that expands from top to bottom further, a discharge portion having a discharge hole for discharging the refrigerant in the discharge muffler from a position higher than the lower end surface of the cover is formed in the upper wall portion of the discharge muffler. The electric motor section has a plurality of refrigerant flow path holes penetrating in the axial direction of the main shaft at intervals in the circumferential direction. The discharge hole of the discharge portion is disposed outside the cover, and at least a part of the discharge hole is disposed inside a virtual circle connecting the innermost ends in the radial direction of the main shaft in each of the plurality of refrigerant flow path holes when viewed in the axial direction. .

Advantages of the Invention

[0008] According to the present disclosure, the hermetic compressor includes a hollow cover into which the refrigerating machine oil lubricating the bearing portion flows, and the cover has a conical shape in which the diameter expands from top to bottom. Since the cover has a conical shape, the centrifugal force acting on the refrigerating machine oil adhering to the inner wall surface of the cover includes a component of force in the diagonally downward direction along the inner wall surface of the cover. That is, a force in the gravitational direction acts on the refrigerating machine oil adhering to the inner wall surface of the cover, and this force in the gravitational direction acts on the refrigerating machine oil when it is ejected from the lower end portion of the cover to the outside of the cover. Therefore, the hermetic compressor can suppress the refrigerating machine oil from being lifted by the refrigerant gas flow and discharged to the outside of the hermetic compressor.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Best Mode for Carrying Out the Invention

[0010] Hereinafter, embodiments will be described with reference to the drawings. Note that the present disclosure is not limited by the embodiments described below. Also, in the following drawings including FIG. 1, the relative dimensional relationships and shapes of each component may be different from the actual ones. Further, in the following drawings, those denoted by the same reference numerals are the same or corresponding ones, and this shall be common throughout the entire text of the specification.

[0011] Embodiment 1. FIG. 1 is a schematic longitudinal sectional view of a hermetic compressor 100 according to Embodiment 1. FIG. 2 is a schematic enlarged view of the vicinity of the upper bearing 14 of the hermetic compressor 100 according to Embodiment 1. FIG. 3 is a plan view of the discharge muffler 17 of the hermetic compressor 100 according to Embodiment 1. In FIG. 3, the cover 60 and the refrigerant flow path hole 23 are shown by dotted lines in order to clearly show the positional relationship between the discharge muffler 17, the cover 60, and the refrigerant flow path hole 23.

[0012] Hereinafter, an example in which the hermetic compressor 100 is a rotary compressor will be described. However, the hermetic compressor 100 is not limited to a rotary compressor, and any compressor may be used as long as a bearing end of a bearing is provided in the path of the discharge gas from the compression mechanism part to the discharge pipe. Note that in the present Embodiment 1, the hermetic compressor 100 is described as a rotary compressor having one cylinder, but it may be a rotary compressor having a plurality of cylinders.

[0013] The hermetic compressor 100 includes, inside a hermetic container 1, a compression mechanism section 10 that compresses a refrigerant, and an electric motor section 20 that drives the compression mechanism section 10. The compression mechanism section 10 and the electric motor section 20 are connected by a main shaft 11, and the compression mechanism section 10 is housed in the lower part of the hermetic container 1 while the electric motor section 20 is housed in the upper part of the hermetic container 1. In the following description, the longitudinal direction of the hermetic container 1 is referred to as the axial direction, the direction perpendicular to this axial direction is referred to as the radial direction, the upper side on the plane of the axial direction is the upward direction, the lower side on the paper is the downward direction, the shaft center side in the radial direction is the inner side, and the inner wall surface side of the hermetic container 1 is the outer side. The hermetic compressor 100 is a so-called vertically-mounted compressor that is used with the main shaft 11 in the gravitational direction.

[0014] Outside the hermetic container 1, a suction muffler 41 is provided adjacent to the hermetic container 1. The suction muffler 41 has the role of storing the liquid refrigerant and muffling the refrigerant sound. The suction muffler 41 is connected to a cylinder 13 (described later) of the compression mechanism section 10 by a suction connection pipe 42. A discharge pipe 43 for discharging the refrigerant compressed by the compression mechanism section 10 is connected to the upper part of the hermetic container 1. An oil reservoir section 50 for storing the refrigeration machine oil is formed in the lower part of the hermetic container 1. A part of the compression mechanism section 10 is immersed in the oil reservoir section 50. The refrigeration machine oil stored in the oil reservoir section 50 is supplied to the main shaft 11, the compression mechanism section 10, the upper bearing 14, the lower bearing 15, etc. through an oil supply hole 11a formed in the main shaft 11. The oil supply hole 11a has a vertical hole 11a1 extending in the axial direction and a plurality of horizontal holes 11a2 extending in the radial direction from the vertical hole 11a1.

[0015] The main shaft 11 transmits the rotational force of the electric motor section 20 to the compression mechanism section 10 and is rotatably supported by the upper bearing 14 and the lower bearing 15. The upper bearing 14 has a bearing portion 14a and a flange portion 14b. The bearing portion 14a is a cylindrical portion that rotatably supports the main shaft 11. The flange portion 14b is at one end in the axial direction of the bearing portion 14a and is a portion that expands in a disc shape from a hole through which the main shaft 11 passes. Also, similarly, the lower bearing 15 has a bearing portion 15a and a flange portion 15b that expands in a disc shape on one side of the bearing portion 15a. The bearing portion 14a and the bearing portion 15a are composed of sliding bearings.

[0016] The compression mechanism section 10 includes an annular cylinder 13, a piston 16 housed in the cylinder 13 and slidably fitted to the eccentric shaft portion 12 of the main shaft 11, and a vane (not shown). The vane is slidably disposed in a vane groove (not shown) provided in the cylinder 13. The radially outer side of the vane is open to the space in the discharge gas atmosphere of the sealed container 1. The openings at both axial ends of the cylinder 13 are closed by the flange portion 14b of the upper bearing 14 and the flange portion 15b of the lower bearing 15 to form a cylinder chamber 30 in the cylinder 13.

[0017] The cylinder 13 is formed with a suction port 40 extending in the radial direction, and a suction connection pipe 42 extending from the suction muffler 41 is connected to the suction port 40. Thereby, the refrigerant sucked into the sealed container 1 from the suction muffler 41 is guided to the cylinder chamber 30. Further, the cylinder 13 is formed with a discharge port (not shown) for discharging the refrigerant compressed in the cylinder chamber 30 from the cylinder chamber 30. The discharge port (not shown) communicates with a through hole (not shown) of a discharge mechanism (not shown) provided in the flange portion 14b of the upper bearing 14, and a discharge muffler 17 is attached to the upper bearing 14 so as to cover the discharge mechanism.

[0018] The discharge muffler 17 has a plate-shaped upper wall portion 17a, a side wall portion 17b extending downward from the outer peripheral edge of the upper wall portion 17a, and a flange portion 17c protruding radially outward from the lower end portion of the side wall portion 17b, and covers the space where the refrigerant compressed by the compression mechanism section 10 is discharged. In FIG. 3, the illustration of the flange portion 17c is omitted. A through hole 17a1 is formed in the central portion of the upper wall portion 17a, and the bearing portion 14a of the upper bearing 14 passes through the through hole 17a1. Further, a discharge portion 171 for discharging the refrigerant in the discharge muffler 17 into the sealed container is formed in the upper wall portion 17a.

[0019] The discharge portion 171 discharges the refrigerant within the cover 60 from a position axially higher than the lower end surface 60b of the cover 60 as shown in FIG. 2. The discharge portion 171 has a discharge hole 171a that penetrates the upper wall portion 17a, and a cylindrical discharge wall 171b that protrudes upward from the peripheral wall of the discharge hole 171a. In FIGS. 1 and 2, the discharge wall 171b is in a flanging shape formed by flanging the upper wall portion 17a of the discharge muffler 17, but the processing method of the discharge wall 171b is not limited, such as welding a cylindrical portion to the peripheral wall of the discharge hole 171a.

[0020] The discharge portion 171 is located outside the outer peripheral edge 60c of the lower end surface 60b of the cover 60. That is, the discharge portion 171 is located outside the cover 60 as viewed axially as shown in FIG. 3. Also, a plurality of discharge portions 171 are formed at intervals in the circumferential direction as shown in FIG. 3.

[0021] The motor unit 20 is disposed above the upper bearing 14. The motor unit 20 includes a stator 22 formed in an annular shape and a rotor 21 supported so as to be rotatable inside the stator 22. The rotor 21 is formed with refrigerant flow path holes 23 that penetrate axially. A plurality of refrigerant flow path holes 23 are formed at intervals in the circumferential direction as shown in FIG. 3. The refrigerant flow path holes 23 serve to guide the refrigerant gas discharged from the compression mechanism portion 10 to the upper part of the sealed container 1, and to drop the refrigerating machine oil guided to the upper part of the sealed container 1 together with the refrigerant gas to the lower part of the sealed container 1. Also, there is a space having the same role as the refrigerant flow path holes 23 between the stator 22 and the sealed container 1, which communicates the upper and lower parts of the sealed container 1.

[0022] Between the motor unit 20 and the discharge muffler 17, a cover 60 is disposed to prevent the refrigerating machine oil from being lifted up and discharged from the hermetic compressor 100. The cover 60 is hollow and penetrates in the axial direction, and is configured in a conical shape in which the diameter expands as it goes from above downward. In this specification, the expression "conical shape" refers to all shapes in which the diameter expands as it goes from above downward, and does not strictly refer to a cone with a pointed tip. The cover 60 is arranged concentrically with the main shaft 11, and the refrigerating machine oil after lubricating the bearing portion 14a is allowed to flow into the cover 60. Specifically, the opening diameter of the upper end portion of the cover 60 is larger than the outer diameter of the bearing portion 14a, and a gap is formed between the cover 60 and the bearing portion 14a. The refrigerating machine oil after lubricating the bearing portion 14a flows out from the upper end 141 of the bearing portion 14a and flows into the cover 60 through the gap. The cover 60 is fixed to the lower end surface of the rotor 21 and rotates together with the rotor 21.

[0023] In addition, in FIGS. 1 and 2 and the like, the upper end of the cover 60 is at a position lower than the upper end 141 of the bearing portion 14a. However, for example, the position of the upper end 141 of the bearing portion 14a may be lower than the position shown in the figure, and the cover 60 may be configured to cover the upper end 141 of the bearing portion 14a when viewed in the radial direction. That is, the axial positional relationship between the upper end of the cover 60 and the upper end 141 of the bearing portion 14a may be opposite to the position shown in the figure. In short, the hermetic compressor 100 only needs to be configured such that the refrigerating machine oil after lubricating the bearing portion 14a flows into the cover 60.

[0024] An oil separation plate 18 for separating the refrigerating machine oil from the refrigerant containing the refrigerating machine oil is fixed to the upper part of the main shaft 11. The oil separation plate 18 may be fixed to the rotor 21. The oil separation plate 18 rotates as the main shaft 11 rotates, and can separate the refrigerating machine oil from the refrigerant by flying the refrigerating machine oil in the outer peripheral direction by centrifugal force. The refrigerating machine oil separated by the oil separation plate 18 falls into the oil reservoir portion 50 through the gap of the motor unit 20 and the like.

[0025] Next, the operation of the hermetic compressor 100 configured as described above will be explained. When the electric motor unit 20 is driven, the rotational force of the electric motor unit 20 is transmitted to the main shaft 11. The rotational force transmitted to the main shaft 11 is transmitted to the eccentric shaft portion 12 attached to the main shaft 11, and the piston 16 eccentrically rotates in the cylinder chamber 30 together with the eccentric shaft portion 12.

[0026] When the piston 16 rotates in the cylinder chamber 30, low-pressure refrigerant is supplied into the cylinder chamber 30 from the suction muffler 41 through the suction connection pipe 42 and the suction port 40. As the piston 16 rotates, the volume of the cylinder chamber 30 decreases, and the refrigerant is compressed. A vane (not shown) is pressed against the piston 16 by the high-pressure refrigerant in the hermetic container 1. The vane slides radially in the vane groove in conjunction with the movement of the piston 16 and serves to partition the cylinder chamber 30 into a low-pressure space and a high-pressure space. The refrigerant sucked into the low-pressure space in the cylinder chamber 30 from the suction port 40 is compressed in the high-pressure space. The compressed refrigerant is once discharged into the discharge muffler 17 from a discharge mechanism (not shown) formed in the upper bearing 14.

[0027] The refrigerant discharged into the discharge muffler 17 is discharged from the discharge portion 171 of the discharge muffler 17 into the internal space of the hermetic container 1. The refrigerant gas discharged into the internal space of the hermetic container 1 flows through the refrigerant flow path hole 23 and the like formed in the electric motor unit 20 and flows into the space above the electric motor unit 20. At this time, the refrigeration machine oil is centrifugally separated from the refrigerant gas by the oil separation plate 18 fixed to the upper part of the main shaft 11, the refrigerant gas is discharged from the discharge pipe 43 to the outside of the hermetic container 1 and flows in the refrigerant circuit, and the refrigeration machine oil is returned to the oil reservoir portion 50 along the inner wall surface of the hermetic container 1.

[0028] In the hermetic compressor 100, the main shaft 11 serves as a centrifugal pump. As the main shaft 11 rotates, the vertical hole 11a1 of the oil supply hole 11a in the main shaft 11 becomes a centrifugal pump and sucks up the refrigerant oil from the oil reservoir 50. The sucked-up refrigerant oil passes through the vertical hole 11a1 and the horizontal hole 11a2, and is supplied to the bearing portion 14a of the lower bearing 15, the cylinder chamber 30, and the upper bearing 14. The refrigerant oil supplied to the bearing portion 14a flows out from the upper end 141 of the upper bearing 14. The refrigerant oil flowing out from the upper end 141 of the upper bearing 14 flows into the cover 60 that rotates with the rotor 21 and collides with and adheres to the inner wall surface 60a. The refrigerant oil adhering to the inner wall surface 60a of the cover 60 reaches the lower end portion of the cover 60 along the inner wall surface 60a and is flung outside the cover 60 by centrifugal force. The refrigerant oil flung outside the cover 60 is sprayed onto the upper wall portion 17a of the discharge muffler 17. After flowing radially outward along the upper wall portion 17a, it flows downward along the side wall portion 17b and is returned to the oil reservoir 50.

[0029] Here, a more detailed operation of the cover 60 will be described.

[0030] FIG. 4 is an explanatory diagram of the operation of the cover 600 of the hermetic compressor according to the comparative example. FIG. 5 is an explanatory diagram of the operation of the cover 60 of the hermetic compressor according to the first embodiment.

[0031] The cover 600 of the comparative example has a cylindrical shape extending in the axial direction as shown in FIG. 4, and the inner diameter is the same throughout the axial direction. Therefore, since the inner wall surface 600a is a vertical surface extending in the vertical direction, the centrifugal force F1 acting on the refrigerant oil 700 in the cover 600 rotating in the direction of arrow R has only a radial component. For this reason, when the refrigerant oil 700 flows out from the lower end portion of the cover 600 to the outside, it is flung in the radial direction, in other words, directly sideways.

[0032] In contrast, the cover 60 of the first embodiment is cone-shaped with a diameter expanding from the top to the bottom as shown in FIG. 5. Therefore, the inner wall surface 60a is an inclined surface that inclines radially outward as it goes downward. Therefore, the centrifugal force F1 acting on the refrigeration oil 70 attached to the inner wall surface 60a of the cover 60 is decomposed into a force component Fa in a diagonally downward direction along the inner wall surface 60a and a force component Fb in a direction perpendicular to the inner wall surface 60a. In this way, the force component Fa in a diagonally downward direction along the inner wall surface 60a acts on the refrigeration oil 70, so that the refrigeration oil 70 is thrown from the lower end of the cover 60 in a diagonally downward direction to the outside in the radial direction. Here, the force component Fa includes a force component in the gravity direction. Therefore, the refrigeration oil 70 thrown from the lower end of the cover 60 is not easily stirred up by the refrigerant gas.

[0033] Therefore, the hermetic compressor 100 of the first embodiment can suppress the refrigeration oil from being stirred up by the refrigerant gas flowing inside the hermetic container 1, specifically, the refrigerant gas discharged from the discharge muffler 17, and being discharged outside the hermetic compressor. The refrigeration oil that is thrown obliquely downward from the lower end of the cover 60 is sprayed onto the upper wall portion 17a of the discharge muffler 17, and then flows downward along the upper wall portion 17a and the side wall portion 17b of the discharge muffler 17, and is returned to the oil reservoir 50.

[0034] Furthermore, the discharge portion 171 discharges the refrigerant from a position higher than the lower end surface 60b of the cover 60. Therefore, the hermetic compressor 100 can separate a path of the refrigeration oil that flows out from the lower end of the cover 60 and returns to the oil reservoir 50 from a path of the refrigerant gas that is discharged from the discharge portion 171 and flows toward the refrigerant flow passage holes 23, etc. As a result, the hermetic compressor 100 can prevent the refrigeration oil that flows out from the lower end of the cover 60 from being mixed with the refrigerant gas that flows out from the discharge portion 171 and flows toward the refrigerant flow passage holes 23, etc., and as a result, the amount of refrigeration oil discharged outside the hermetic compressor can be reduced.

[0035] Also, the axial distance G between the lower end surface 60b of the cover 60 and the upper wall portion 17a of the discharge muffler 17 is preferably made significantly smaller than the radial distance L between the lower end surface 60b of the cover 60 and the upper bearing 14 (G < L). By doing so, most of the refrigerant oil discharged from the lower end portion of the cover 60 adheres directly to and is captured on the upper wall portion 17a of the discharge muffler 17 without being lifted up. Further, the axial distance H between the lower end surface 60b of the cover 60 and the upper end surface 171a1 of the discharge portion 171 is preferably made larger than the axial distance G between the lower end surface 60b and the upper wall portion 17a of the discharge muffler 17 (H > G). By doing so, the effect of preventing the refrigerant oil discharged from the lower end portion of the cover 60 from being lifted up by the gas discharged from the discharge portion 171 is enhanced.

[0036] The hermetic compressor 100 of Embodiment 1 is a compressor in which the oil in the oil reservoir portion 50 formed in the hermetic container 1 is supplied to the bearing portion 15a through the oil supply hole 11a formed in the main shaft 11. The hermetic compressor 100 includes a hollow cover 60 that is fixed to the electric motor portion 20 and is concentrically arranged on the main shaft 11 between the electric motor portion 20 and the compression mechanism portion 10, and into which the refrigerant oil that lubricates the bearing portion 15a flows. The cover 60 has a conical shape in which the diameter expands from top to bottom.

[0037] With the above configuration, the inner wall surface 60a of the cover 60 of the hermetic compressor 100 becomes an inclined surface that slopes radially outward as it goes downward. Therefore, the centrifugal force F1 acting on the refrigerant oil 70 adhering to the inner wall surface 60a has a downward oblique force component Fa along the inner wall surface 60a. That is, a force in the gravitational direction acts on the refrigerant oil adhering to the inner wall surface 60a of the cover 60, and this force in the gravitational direction acts on the refrigerant oil when it is flung out of the lower end portion of the cover 60 to the outside of the cover. Therefore, the hermetic compressor 100 can suppress the refrigerant oil flowing out from the lower end portion of the cover 60 from being lifted up by the refrigerant gas flowing in the hermetic container 1 and discharged outside the hermetic compressor.

[0038] The hermetic compressor 100 of the first embodiment also includes a discharge muffler 17 that covers a space into which the refrigerant compressed by the compression mechanism 10 is discharged. The discharge muffler 17 is disposed between the compression mechanism 10 and the electric motor 20, and has a plate-shaped upper wall 17a having a through hole 17a1 through which the bearing 15a is inserted, and a side wall 17b extending downward from the outer circumferential edge of the upper wall 17a. The upper wall 17a of the discharge muffler 17 is formed with a discharge section 171 having a discharge hole 171a that discharges the refrigerant in the discharge muffler 17 from a position higher than the lower end surface 60b of the cover 60.

[0039] With the above-mentioned configuration, the hermetic compressor 100 can separate the path of the refrigeration oil that flows out from the lower end of the cover 60 and returns to the oil reservoir 50, from the path of the refrigerant gas that is discharged from the discharge port 171 and flows toward the refrigerant flow path hole 23, etc. This makes it possible for the hermetic compressor 100 to prevent the refrigeration oil that flows out from the lower end of the cover 60 from being mixed with the refrigerant gas flowing inside the hermetic container 1, and as a result, the amount of oil discharged outside the hermetic compressor can be reduced.

[0040] Embodiment 2 FIG. 6 is a schematic enlarged view of the vicinity of the upper bearing 14 of the hermetic compressor 100 according to the second embodiment. The configuration of the second embodiment is the same as that shown in the first embodiment except for the discharge muffler 17. FIG. 7 is a plan view of the discharge muffler 17 of the hermetic compressor 100 according to the second embodiment. In FIG. 7, the cover 60 and the refrigerant passage hole 23 are shown by dotted lines in order to clearly show the positional relationship between the discharge muffler 17, the cover 60, and the refrigerant passage hole 23. In addition, the flange portion 17c is not shown in FIG. 7. The following description will focus on the configuration of the second embodiment that is different from the first embodiment, and the configuration not described in the second embodiment is the same as the first embodiment.

[0041] The discharge muffler 17 in the second embodiment has a recess 172 recessed downward in the upper wall portion 17a of the discharge muffler 17 in the first embodiment. As shown in FIG. 7, a plurality of recesses 172 are formed at intervals in the circumferential direction. Although FIG. 7 shows an example in which three recesses 172 are provided, the number of recesses 172 is not limited. The recess 172 extends radially outward from a position radially inward from the inner peripheral edge 60d of the lower end surface 60b of the cover 60 to the side wall portion 17b as viewed in the axial direction, and is open radially outward. Due to this recess 172, a part of the cover 60 does not face the upper wall portion 17a of the discharge muffler 17, and is open downward. Specifically, the open portion 62, which is the portion open downward, is a portion surrounded by the inner peripheral edge 60d of the lower end surface 60b of the cover 60 and the outer peripheral edge 17aa of the upper wall portion 17a of the discharge muffler 17 as viewed in the axial direction, as shown in FIG. 7, and is the portion indicated by dots.

[0042] With the above-mentioned configuration, the refrigeration oil flowing out from the lower end of the cover 60 easily flows from the open portion 62, which is wider than the gap between the lower end surface 60b of the cover 60 and the upper wall portion 17a of the discharge muffler 17, to the recess 172. The arrows in FIG. 6 indicate the flow of the refrigeration oil in the cover 60 from the open portion 62 to the recess 172. In this way, the refrigeration oil flowing out from the lower end of the cover 60 easily flows from the open portion 62 to the recess 172, so to speak, concentrating and flowing in the recess 172. This allows the hermetic compressor 100 to separate the discharge flow path of the refrigeration oil from the discharge portion 171. Therefore, the hermetic compressor 100 can suppress the refrigeration oil from being stirred up by the refrigerant gas flow discharged from the discharge portion 171, compared to a case where the recess 172 is not provided in the discharge muffler 17.

[0043] The hermetic compressor 100 of the second embodiment has the same effects as those of the first embodiment, and also has the following effects by providing the recess 172 in the discharge muffler 17. The hermetic compressor 100 of the second embodiment can separate the discharge flow path of the refrigerating machine oil from the refrigerating machine gas flow path from the discharge part 171, and can prevent the refrigerating machine oil from being entrained in the refrigerating machine gas flow and being discharged outside the hermetic compressor.

[0044] Embodiment 3 FIG. 8 is a schematic enlarged view of the vicinity of the upper bearing 14 of the hermetic compressor 100 according to Embodiment 3. In Embodiment 3, the configuration other than the discharge muffler 17 is the same as that shown in Embodiment 2. Hereinafter, the description will focus on the configuration in which Embodiment 3 differs from Embodiment 2, and the configuration not described in the present Embodiment 3 is the same as that in Embodiment 2.

[0045] In the discharge muffler 17 in Embodiment 3, the configuration of the discharge portion 171 is different from that in Embodiment 1 and Embodiment 2. In the discharge muffler 17 of Embodiment 3, the upper wall portion 17a is configured in a stepped shape to form the discharge portion 171. Specifically, the discharge portion 171 of Embodiment 3 has a convex portion 171c that protrudes upward from the upper wall portion 17a to a position higher than the height of the lower end surface 60b of the cover 60, and a discharge hole 171a that penetrates in the axial direction is formed in the convex portion 171c.

[0046] With the above configuration, the discharge portion 171 discharges the refrigerant gas in the cover 60 from a position axially higher than the lower end surface 60b of the cover 60. Therefore, the hermetic compressor 100 of Embodiment 3 can obtain the same effect as that of Embodiment 1. Note that FIG. 8 shows a configuration in which the discharge muffler 17 has the recess 172 of Embodiment 2, but the discharge muffler 17 of Embodiment 3 may be configured without the recess 172. When the discharge muffler 17 of Embodiment 3 does not have the recess 172, the same effect as that of Embodiment 1 can be obtained, and when it has the recess 172, the same effect as that of Embodiment 2 can be obtained.

[0047] In addition, when the discharge portion 171 of Embodiment 1 is formed by burring a sheet metal, the height of the discharge wall 171b is limited by the diameter of the discharge hole 171a. On the other hand, since the discharge portion 171 of Embodiment 3 has a stepped shape, the convex portion 171c can be formed by pressing or the like, and the height of the discharge portion 171 can be increased with a simple structure regardless of the diameter of the discharge hole 171a. Since the hermetic compressor 100 of Embodiment 3 can increase the height of the discharge portion 171, the separation effect between the oil discharge flow path and the refrigerant gas flow path can be enhanced.

[0048] Embodiment 4. Embodiment 4 specifies the radial positional relationship between the discharge holes 171a of the discharge muffler 17 and the refrigerant flow path holes 23 in Embodiments 1 to 3 above.

[0049] FIG. 9 is a plan view of the discharge muffler 17 of the hermetic compressor 100 according to Embodiment 4. In FIG. 9, to clarify the positional relationship between the discharge muffler 17, the cover 60, and the refrigerant flow path holes 23, the outer peripheral edge 60c of the cover 60 and the refrigerant flow path holes 23 are shown by dotted lines. In FIG. 9, C is a virtual circle connecting the innermost ends, which are the radially inner ends of the respective refrigerant flow path holes 23. FIG. 10 is a schematic enlarged view near the upper bearing 14 of the hermetic compressor 100 according to Embodiment 4. The hermetic compressor 100 according to Embodiment 4 is arranged such that at least a part of the discharge holes 171a is located inside the virtual circle C.

[0050] The effects of the above configuration will be described in comparison with a comparative example.

[0051] FIG. 11 is a plan view of the discharge muffler of the hermetic compressor according to the comparative example. FIG. 12 is a schematic enlarged view near the upper bearing of the hermetic compressor according to the comparative example.

[0052] In both the case of Embodiment 4 and the comparative example, the refrigerating machine oil flowing out from the lower end portion of the cover 60 is sprayed onto the upper wall portion 17a of the discharge muffler 17. A part of the refrigerating machine oil sprayed onto the upper wall portion 17a of the discharge muffler 17 may collide with the discharge wall 171b of the discharge portion 171 and be rolled up, or may be rolled up by the refrigerant gas flow or the like. In FIGS. 10 and 12, the white arrows indicate the swirling flow of the refrigerant gas, and the solid arrows indicate the flow of the refrigerating machine oil.

[0053] Here, in the comparative example shown in FIGS. 11 and 12, the discharge holes 1710 are located outside the virtual circle C when viewed in the axial direction. In this case, since there is no element that obstructs the flow of the refrigerating machine oil rolled up in the path from the lower end portion of the cover 60 to the refrigerant flow path holes 23, the refrigerating machine oil rolled up as described above easily directly enters the refrigerant flow path holes 23.

[0054] On the other hand, in the hermetic compressor 100 of Embodiment 4, as shown in FIGS. 9 and 10, at least a part of the discharge hole 171a is located inside the virtual circle C. In this case, the refrigerating machine oil wound up as described above is blown centrifugally by the refrigerant gas flow discharged from the discharge hole 171a and the swirling flow generated by the rotation of the rotor 21, and does not directly face the refrigerant flow path hole 23.

[0055] More specifically described. The swirling flow generated in the vicinity of the discharge portion 171 by the refrigerant flow discharged from the discharge hole 171a is assumed to act from the upper part to the outer peripheral part of the discharge wall 171b and not to act inside the discharge wall 171b. Here, comparing FIG. 10 and FIG. 12, in the comparative example shown in FIG. 12, the swirling flow indicated by the white arrow is located radially outside compared to FIG. 10 and is away from the lower end portion of the cover 60. For this reason, in the configuration of the comparative example, the refrigerating machine oil flowing out from the lower end portion of the cover 60 and wound up is less likely to be obstructed by the swirling flow and directly face the refrigerant flow path hole 23.

[0056] On the other hand, in the hermetic compressor 100 of Embodiment 4, as shown in FIG. 10, the swirling flow has moved radially inward compared to the comparative example and is approaching the lower end portion of the cover 60. For this reason, the refrigerating machine oil flowing out from the lower end portion of the cover 60 and wound up is caught by the swirling flow from the discharge hole 171a and receives centrifugal force, and does not directly face the refrigerant flow path hole 23.

[0057] From the above, the hermetic compressor 100 of Embodiment 4 can further suppress the refrigerating machine oil flowing out from the lower end portion of the cover 60 from being wound up and entering the refrigerant flow path hole 23. As a result, the hermetic compressor 100 of Embodiment 4 can further suppress the refrigerating machine oil from being discharged outside the hermetic compressor.

[0058] The hermetic compressor 100 of Embodiment 4 can obtain the same effects as those of Embodiments 1 to 3, and by arranging at least a part of the discharge hole 171a inside the virtual circle C, it is possible to further suppress the refrigerating machine oil from being discharged outside the hermetic compressor.

Explanation of Signs

[0059] 1 Sealed container, 10 Compression mechanism section, 11 Main shaft, 11a Oil supply hole, 11a1 Vertical hole, 11a2 Horizontal hole, 12 Eccentric shaft section, 13 Cylinder, 14 Upper bearing, 14a Bearing section, 14b Flange section, 15 Lower bearing, 15a Bearing section, 15b Flange section, 16 Piston, 17 Discharge muffler, 17a Upper wall section, 17a1 Through hole, 17aa Outer peripheral edge, 17b Side wall section, 17c Flange section, 18 Oil separation plate, 20 Electric motor section, 21 Rotor, 22 Stator, 23 Refrigerant flow path hole, 30 Cylinder chamber, 40 Suction port, 41 Suction muffler, 42 Suction connection pipe, 43 Discharge pipe, 50 Oil reservoir section, 60 Cover, 60a Inner wall surface, 60b Lower end surface, 60c Outer peripheral edge, 60d Inner peripheral edge, 62 Opening section, 70 Refrigeration machine oil, 100 Hermetic compressor, 141 Upper end, 171 Discharge section, 171a Discharge hole, 171a1 Upper end surface, 171b Discharge wall, 171c Protrusion, 172 Depression.

Claims

1. A hermetic compressor comprising: a sealed container formed with an oil sump for storing refrigerating oil; a compression mechanism disposed within the sealed container for compressing refrigerant; a motor unit disposed above the compression mechanism within the sealed container for driving the compression mechanism; a main shaft for transmitting the rotational force of the motor unit to the compression mechanism; and a bearing unit for rotatably supporting the main shaft below the motor unit, wherein the oil in the oil sump is supplied to the bearing unit through an oil supply hole formed in the main shaft, a hollow cover fixed to the motor unit and disposed concentrically with respect to the main shaft between the motor unit and the compression mechanism, into which refrigerating oil lubricating the bearing unit flows, a discharge muffler disposed between the compression mechanism and the motor unit, having a plate-shaped upper wall portion having a through hole through which the bearing unit passes and a side wall portion extending downward from an outer peripheral edge of the upper wall portion, and covering a space in which refrigerant compressed by the compression mechanism is discharged, the cover being conical with a diameter increasing from top to bottom, a discharge portion having a discharge hole for discharging the refrigerant in the discharge muffler is formed in the upper wall portion of the discharge muffler at a position higher than a lower end surface of the cover, the motor unit has a plurality of refrigerant flow path holes penetrating in an axial direction of the main shaft at intervals in a circumferential direction, the discharge hole of the discharge portion is disposed outside the cover, and at least a part of the discharge hole is disposed inside a virtual circle connecting the innermost ends in a radial direction of the main shaft in each of the plurality of refrigerant flow path holes when viewed in the axial direction. The hermetic compressor is so arranged.

2. The discharge muffler has a recess recessed downward in the upper wall portion, The recess is formed to extend radially outward from a position radially inside the inner peripheral edge of the lower end surface of the cover to the side wall portion when viewed in the axial direction of the main shaft. The hermetic compressor according to Claim 1.

3. The discharge portion has a convex portion protruding upward from the upper wall portion to a position higher than a height of a lower end surface of the cover, and the discharge hole is formed to penetrate in the axial direction of the main shaft in the convex portion. The hermetic compressor according to Claim 1 or Claim 2.

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