Hermetic compressor

Abstract

To easily scatter oil even in low speed operation in comparison with a constitution in which a skirt part expanded outward in the radial direction is connected to an upper part of a large end part externally fitted to a crank pin of a connecting rod.SOLUTION: A hermetic compressor comprising: a compression unit provided in an upper portion of a sealed container and configured to compress a refrigerant by a reciprocating motion of a piston; an electric unit provided in a lower portion of the sealed container; and a crankshaft provided in the sealed container in a vertical direction and rotated by the electric unit, wherein the crankshaft has a crank pin connected to the piston by a connecting rod at an upper end thereof, and the crank pin has an opening at an upper portion thereof and has a scattering portion for scattering lubricating oil in a partial range of an outer periphery of the opening.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a hermetic compressor. [Background technology]

[0002] Patent Document 1 describes a hermetic compressor in which a compression device is provided at the top of a casing and an electric motor is provided at the bottom, the piston of the compression device is connected to a crankpin provided at the end of a shaft extending upward from the electric motor by a connecting rod, and lubricating oil is scattered from an opening provided in the crankpin. In this hermetic compressor, a skirt portion that expands radially outward is connected to the top of the big end that is attached to the crankpin of the connecting rod, and the lubricating oil that comes out from the crankpin hits the inclined surface on the inner surface of the skirt portion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 60-252178 Summary of the Invention [Problem to be solved by the invention]

[0004] Consider a case where a skirt portion that expands radially outward is attached to the top of the big end of the connecting rod, which is attached to the crank pin. In this case, the lubricating oil scatters on the inner surface of the skirt portion, making it difficult to collect, and it is not possible to increase the amount of oil supplied. Therefore, during low-speed operation, the lubricating oil is less likely to scatter.

[0005] The object of the present invention is to make it easier for lubricating oil to splash even during low-speed operation, compared to a configuration in which a skirt portion that expands radially outward is connected to the upper part of the big end that is attached to the crank pin of the connecting rod. [Means for solving the problem]

[0006] To achieve this object, the present invention provides a hermetic compressor comprising: a compression section provided in an upper part of a sealed container and compressing a refrigerant by the reciprocating motion of a piston; an electric motor provided in a lower part of the sealed container; and a crankshaft provided in the vertical direction within the sealed container and rotated by the electric motor, wherein the crankshaft has a crankpin at its upper end connected to the piston by a connecting rod, and the crankpin has an opening at its upper part and a scattering section for scattering lubricating oil within a partial range of the outer periphery of the opening.

[0007] The crank pin may have a scattering portion at one location on the outer periphery of the opening. In this case, the one location may be the location among multiple locations on the outer periphery of the opening that is the farthest from the center of rotation of the crankshaft. Alternatively, the one location may be the location among multiple locations on the outer periphery of the opening that is the farthest from the center of rotation of the crankshaft, shifted in the opposite direction to the rotation direction of the crankshaft to an extent that does not impair the lubricating oil scattering performance.

[0008] The scattering portion may be a portion where part of the crank pin is cut out. In this case, the portion may be a V-shaped notch in part of the crank pin.

[0009] The scattering portion may be a portion provided on another component attached to the crank pin. In that case, other parts may be added to splash the lubricant. Alternatively, the other parts may be added for purposes other than scattering lubricating oil. In this case, the portion may be protruded in the shape of a spout. Alternatively, the portion may be a V-shaped cutout in part of another component. [Effects of the Invention]

[0010] According to the present invention, lubricating oil is more likely to splash even during low-speed operation than in a configuration in which a skirt portion that expands radially outward is connected to the upper part of the big end that is attached to the crank pin of the connecting rod. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view of a hermetic compressor according to an embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view of a crank pin with an attachment attached thereto in the present embodiment. [Figure 3] FIG. 2 is a top view of the hermetic compressor according to the embodiment. [Figure 4] FIG. 2 is a top view of the hermetic compressor according to the embodiment. [Figure 5] FIG. 2 is a top view of a hermetic compressor according to a first modified example. [Figure 6] FIG. 2 is a top view of a hermetic compressor according to a first modified example. [Figure 7] FIG. 10 is a perspective view of a crank pin in a second modified example. [Figure 8] FIG. 11 is a perspective view showing a state in which a balance weight is attached to a crank pin in a third modified example. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0013] [Hermetic compressor] 1 is a cross-sectional view of a hermetic compressor 1 according to the present embodiment. As shown in the figure, the hermetic compressor 1 includes a hermetic container 10, a compression device 20, and a drive motor 30. A hermetic space is formed inside the hermetic container 10, and the compression device 20 and the drive motor 30 are provided in this hermetic space. The compression device 20 compresses a refrigerant, and the drive motor 30 drives the compression device 20.

[0014] The compression device 20 includes a frame 21, a cylinder 22, and a compression chamber 23. The compression device 20 further includes a piston 24, a cylinder head 25, and a valve device 26. The cylinder 22 is formed integrally with the frame 21. The cylinder 22 is configured so that a piston 24 is housed at one end and a cylinder head 25 is coupled to the other end. The compression chamber 23 is formed inside the cylinder 22 between the piston 24 and the cylinder head 25 . The piston 24 is configured to reciprocate linearly within the cylinder 22 . The cylinder head 25 seals the other end of the cylinder 22. A refrigerant suction chamber 251 and a refrigerant discharge chamber 252 are formed within the cylinder head 25. The refrigerant suction chamber 251 is configured to guide the refrigerant from the suction pipe to the compression chamber 23. The refrigerant discharge chamber 252 is configured to guide the refrigerant discharged from the compression chamber 23 to the discharge pipe. Although not shown, the suction pipe and the discharge pipe are disposed on one side of the sealed container 10. The suction pipe guides the refrigerant from an evaporator (not shown) of the refrigeration cycle to the sealed container 10. The discharge pipe guides the refrigerant from the sealed container 10 to a condenser (not shown) of the refrigeration cycle. The valve device 26 is interposed between the cylinder 22 and the cylinder head 25. The valve device 26 controls the flow of refrigerant drawn from the refrigerant suction chamber 251 into the compression chamber 23. The valve device 26 also controls the flow of refrigerant discharged from the compression chamber 23 to the refrigerant discharge chamber 252.

[0015] The compression device 20 is an example of a compression unit that is provided in the upper part of a sealed container and compresses the refrigerant by the reciprocating motion of a piston.

[0016] The drive motor 30 linearly reciprocates the piston 24 to compress the refrigerant in the compressor 20. The drive motor 30 includes a stator 31 and a rotor 32. The stator 31 is fixed to the frame 21 facing the compressor 20. The stator 31 generates a magnetic field. The rotor 32 is rotatably provided outside the stator 31 at a distance from the stator 31. The rotor 32 rotates due to electromagnetic interaction with the stator 31.

[0017] The drive motor 30 is an example of an electric motor provided in the lower part of the sealed container.

[0018] The drive motor 30 is coupled to a crankshaft 33, which is coupled to the compressor 20. That is, the crankshaft 33 is inserted into a hollow portion 27 formed in the center of the frame 21 and rotatably supported therein. One side of the crankshaft 33 is connected to a bottom portion 321 of the rotor 32 so that the crankshaft 33 rotates together with the rotor 32. The other side of the crankshaft 33 protrudes from the frame 21 to form a crankpin 34. The crankpin 34 is not concentric with the crankshaft 33. Therefore, the crankpin 34 revolves around the longitudinal axis Z of the crankshaft 33 as the rotor 32 rotates. The crankpin 34 is connected to a connecting rod 28, which is connected to the piston 24. Therefore, the connecting rod 28 converts the eccentric rotational motion of the crankpin 34 into the linear reciprocating motion of the piston 24.

[0019] The crankshaft 33 is an example of a crankshaft that is provided in the sealed container in the vertical direction and is rotated by an electric motor. The crank pin 34 is an example of a crank pin connected to a piston at the upper end of the crankshaft by a connecting rod.

[0020] Now, let's assume that a current is applied to the hermetic compressor 1. The stator 31 generates a magnetic field, and the rotor 32 rotates due to electromagnetic interaction with the stator 31. This causes the crank pin 34 of the crankshaft 33 to revolve around the longitudinal axis Z of the crankshaft 33. The crank pin 34 then causes the piston 24, connected via the connecting rod 28, to linearly reciprocate within the compression chamber 23. This linear reciprocating motion of the piston 24 creates a pressure difference between the inside and outside of the compression chamber 23. Therefore, the further the piston 24 moves from the cylinder head 25, the larger the compression chamber 23 expands. Refrigerant guided from the evaporator of the refrigeration cycle to the refrigerant suction chamber 251 through the suction pipe is drawn into the compression chamber 23. Meanwhile, the piston 24 presses against the compression chamber 23 as it approaches the cylinder head 25, compressing the refrigerant within the compression chamber 23. The compressed refrigerant is then discharged from the compression chamber 23 into the refrigerant discharge chamber 252. The refrigerant is then guided by a discharge pipe from the refrigerant discharge chamber 252 to the condenser of the refrigeration cycle.

[0021] Furthermore, in the hermetic compressor 1, lubricating oil (hereinafter also simply referred to as "oil") is supplied to lubricate and cool the moving parts of the compression device 20 and the drive motor 30. Such lubrication and cooling of the moving parts is performed to prevent wear due to excessive friction between the moving parts. For this reason, an oil storage space 11 is formed in the lower part of the hermetic container 10 in which a predetermined amount of oil is stored.

[0022] A viscosity pump 36 is provided at the lower end of the crankshaft 33. The viscosity pump 36 is a pump that sucks up oil from the oil storage space 11 by using the viscosity of the oil in contact with the groove on the outer periphery of the cylinder. However, since Figure 1 is a cross-sectional view, only the portion of the groove on the outer periphery of the cylinder that intersects with the cross section is shown.

[0023] Here, we will explain the lubrication and cooling of the moving parts between the cylinder 22 and the piston 24. To lubricate and cool the moving parts, an oil passage 35 is formed in the crankshaft 33. The oil passage 35 guides oil from the oil storage space 11 to the crankpin 34. The crankshaft 33 is also provided with a centrifugal pump 37. The centrifugal pump 37 guides oil from the oil storage space 11 to the moving parts using centrifugal force generated by the rotation of the crankshaft 33. The centrifugal pump 37 has a spiral groove that slopes upward in the counter-rotational direction of the crankshaft 33. However, because FIG. 1 is a cross-sectional view, only the portion of the spiral groove of the centrifugal pump 37 that intersects with the cross section is shown. The upper end of the centrifugal pump 37 is connected to the lower end of the oil passage 35, and the lower end of the centrifugal pump 37 is connected to the upper end of the viscous pump 36. The viscosity pump 36 collects oil from the oil storage space 11 during compression of the refrigerant and provides a path for guiding the oil to the centrifugal pump 37. Therefore, the oil flows into the oil passage 35 through the centrifugal pump 37 by the centrifugal force of the crankshaft 33. The oil also flows from the oil passage 35 to the crankpin 34. The oil is then splashed onto the moving parts of this case from the opening 341 of the crankpin 34. The oil then cools and lubricates the moving parts of this case.

[0024] In this way, in a reciprocating compressor such as the hermetic compressor 1, oil is supplied to the outer periphery of the piston 24. Specifically, oil is supplied to the outer periphery of the piston 24 by splashing from the opening 341 at the top of the crankpin 34. However, in recent years, in order to improve energy conservation, there has been a demand to slow down the rotation speed of the crankshaft 33. When the rotation speed of the crankshaft 33 is slowed down, the centrifugal force is reduced, making it difficult for oil to splash.

[0025] Therefore, in this embodiment, an attachment 40 is attached to the upper part of the crank pin 34. A protrusion 401 is provided at one location on the outer periphery of the attachment 40.

[0026] 2 is a perspective view of the attachment 40 attached to the crank pin 34. As shown in the figure, the outer diameter of the attachment 40 is larger than the outer diameter of the crank pin 34. The attachment 40 also has an opening 402. Furthermore, the attachment 40 has a protrusion 401 in the shape of a spout at one location on its outer periphery. With attachment 40 having this spout-shaped protrusion 401, oil supplied to crankpin 34 tends to gather in one place. Also, with such attachment 40, oil splashes from one place at a location whose outer diameter is larger than crankpin 34. Therefore, oil splashes easily even during low-speed operation, improving the reliability of the sliding portion of piston 24. Here, the spout shape may be considered to be beak-shaped.

[0027] Alternatively, although not shown, the attachment 40 may be provided with a notch at one location on the outer periphery instead of the protrusion 401 .

[0028] Although the attachment 40 is provided with one protrusion 401 at one location on the outer periphery here, this is not limitative. The attachment 40 may be provided with two or more protrusions 401 in a partial range on the outer periphery.

[0029] The protrusion 401 is an example of a scattering portion that is provided in a partial range of the outer periphery of the opening at the top of the crank pin and that scatters lubricating oil. The attachment 40 is an example of another part added to the crank pin, and is also an example of another part added to disperse lubricating oil.

[0030] Incidentally, oil is scattered outward from the vertex of the crankpin 34 in the eccentric direction (hereinafter referred to as the "eccentric vertex"). Here, the eccentric vertex is the point where the outer diameter is maximum when the crankpin 34 revolves around the vertical axis Z. In other words, the eccentric vertex is the point on the outer periphery of the crankpin 34 that is the farthest from the center of rotation of the crankshaft 33. Therefore, providing the protrusion 401 of the attachment 40 at the position of the eccentric vertex is effective in preventing oil scattering.

[0031] 3 and 4 are top views of the hermetic compressor 1 according to the present embodiment. Of these, FIG. 3 is a top view of the hermetic compressor 1 when the piston 24 is at bottom dead center. FIG. 4 is a top view of the hermetic compressor 1 when the piston 24 is at top dead center. The protrusion 401 of the attachment 40 always faces radially outward of a circle C centered on the vertical axis Z. For example, in the state of FIG. 3, the protrusion 401 of the attachment 40 faces away from the piston 24 in the radial direction of the circle C. In the state of FIG. 4, the protrusion 401 of the attachment 40 faces toward the piston 24 in the radial direction of the circle C. In other words, the protrusion 401 of the attachment 40 always faces in the direction of the centrifugal force generated when the crank pin 34 revolves around the vertical axis Z.

[0032] The inventors considered lowering the current minimum rotation speed of the reciprocating compressor to a target minimum rotation speed from the viewpoint of improving energy conservation. 2 is not installed, oil splashes up to the piston 24 even at the current minimum rotational speed. However, it was found that the oil splash limit is reached at a predetermined speed higher than the target minimum rotational speed. It was also found that at the target minimum rotational speed, the oil drips and does not reach the piston 24. On the other hand, when the attachment 40 shown in Fig. 2 was installed, it was confirmed that oil was scattered even at a predetermined speed slower than the target minimum rotation speed. It was also confirmed that oil was able to reach the sliding part of the piston 24 sufficiently at the target minimum rotation speed.

[0033] [First Modification] 3, when the piston 24 is at bottom dead center, the piston 24 is most exposed to the outside of the cylinder 22. However, in this case, the oil splashes outward from the eccentric apex of the crank pin 34, in the opposite direction to the piston 24. Therefore, the oil does not splash onto the piston 24. On the other hand, when the piston 24 is at top dead center as shown in Figure 4, oil is splashed in the direction of the piston 24. However, in this case, the piston 24 is hidden inside the cylinder 22. Therefore, the oil gets on the part 221 of the cylinder 22 on the crankpin 34 side. Then, as the crankpin 34 rotates further, the oil drips down and gets on the exposed piston 24. In other words, although the oil arrives with a delay relative to the rotation of the crankpin 34, it actually reaches the piston 24. However, the oil is more likely to get on if the time between the oil splashing and the piston 24 being exposed to the outside is shortened.

[0034] Therefore, in the first modified example, the position of the protrusion 401 of the attachment 40 is shifted in the direction opposite to the rotation direction of the crankshaft 33. 5 and 6 are top views of a hermetic compressor 1 according to a first modified example. FIG. 5 is a top view of the hermetic compressor 1 when the piston 24 is at bottom dead center. FIG. 6 is a top view of the hermetic compressor 1 when the piston 24 is at top dead center. As shown in FIGS. 5 and 6, the angle from the center of the crankpin 34 to the protrusion 401 is tilted compared to FIGS. 3 and 4. Specifically, the angle to the protrusion 401 is tilted by an angle θ in the opposite direction to the rotational direction of the crankshaft 33 relative to the angle to the eccentric apex. If the angle θ is within a certain angle, oil will splash from the protrusion 401 due to its viscosity. On the other hand, if the angle θ exceeds a certain angle, oil will splash from the eccentric apex. Therefore, the angle θ is preferably set to an angle that does not impair oil splashing performance.

[0035] [Second Modification] In the second modification, instead of attaching the attachment 40 to the crank pin 34, a portion of the crank pin 34 is cut out.

[0036] 7 is a perspective view of the crank pin 34 in the second modified example. As shown in the figure, the crank pin 34 in the second modified example has a notch 411 formed at one location on the outer periphery. Here, the notch 411 has a V-shape. By providing the notch 411 in one location on the outer periphery of the crank pin 34 in this way, the oil tends to gather in one location. As a result, the oil tends to scatter. Another advantage is that the attachment 40 is no longer necessary, which reduces costs.

[0037] Although the crankpin 34 has one notch 411 formed at one location on the outer periphery, the present invention is not limited to this. The crankpin 34 may have two or more notches 411 formed in a partial range on the outer periphery.

[0038] The notch 411 is an example of a scattering portion that is provided in a partial range of the outer periphery of the opening at the top of the crank pin and that allows lubricating oil to be scattered.

[0039] [Third Modification] In a third modified example, another component is attached to the crank pin 34 instead of the attachment 40. Then, a portion of the other component is cut out. For example, a balance weight may be fastened to the crank pin 34. The balance weight is a weight that suppresses vibrations that occur due to imbalance during rotation of the crankshaft 33. Here, a balance weight will be used as an example of the other component.

[0040] 8 is a perspective view of the balance weight 42 attached to the crank pin 34 in the third modified example. As shown in the figure, the balance weight 42 in the third modified example has a notch 421 formed in one location on the outer periphery of the fastening portion. Here, the notch 421 has a V-shape. By providing notch 421 in one location on the outer periphery of the fastening portion of balance weight 42 in this way, oil tends to gather in one location. As a result, oil tends to splash. Also, by using a part that is added for purposes other than splashing oil, there is an advantage in that the number of parts does not need to be increased.

[0041] Alternatively, although not shown, the other component may have a spout-shaped protrusion at one location on the outer periphery of the fastening portion instead of the notch 421.

[0042] Although the attachment 40 is provided with one protrusion 401 at one location on the outer periphery here, this is not limitative. The attachment 40 may be provided with two or more protrusions 401 in a partial range on the outer periphery.

[0043] The notch 421 is an example of a scattering portion that is provided in a partial range of the outer periphery of the opening at the top of the crank pin and that scatters lubricating oil. The balance weight 42 is an example of another part added to the crank pin, and is also an example of another part added for a purpose other than scattering lubricating oil. [Explanation of symbols]

[0044] 1... hermetic compressor, 10... hermetic container, 11... oil storage space, 20... compression device, 21... frame, 22... cylinder, 23... compression chamber, 24... piston, 25... cylinder head, 26... valve device, 28... connecting rod, 30... drive motor, 31... stator, 32... rotor, 33... crankshaft, 34... crank pin, 35... oil flow path, 36... viscous pump, 37... centrifugal pump, 40... attachment, 401... protrusion, 411... notch, 42... balance weight, 421... notch

Claims

1. a compression section provided in an upper portion of the sealed container and compressing the refrigerant by reciprocating motion of a piston; an electric motor provided at a lower portion inside the sealed container; a crankshaft provided vertically within the sealed container and rotated by the electric motor; Equipped with The crankshaft has a crank pin at its upper end that is connected to the piston by a connecting rod, The crank pin has an opening at an upper portion thereof, and a scattering portion for scattering lubricating oil within a partial range of the outer periphery of the opening.

2. The hermetic compressor according to claim 1 , wherein the crank pin has the scattering portion at one location on the outer periphery of the opening.

3. The hermetic compressor according to claim 2 , wherein the one location is a location among a plurality of locations on the outer periphery of the opening that is farthest from the center of rotation of the crankshaft.

4. 3. The hermetic compressor according to claim 2, wherein the one location is a location among a plurality of locations on the outer periphery of the opening that is farthest from the center of rotation of the crankshaft, and is shifted in a direction opposite to the rotation direction of the crankshaft to an extent that does not impair the lubricating oil scattering performance.

5. The hermetic compressor according to claim 1 , wherein the scattering portion is a cutout portion of the crank pin.

6. The hermetic compressor according to claim 5 , wherein the portion is a V-shaped notch in a part of the crank pin.

7. 2. The hermetic compressor according to claim 1, wherein the scattering portion is a portion provided on another component attached to the crank pin.

8. 8. The hermetic compressor according to claim 7, wherein the other parts are added to disperse the lubricating oil.

9. 8. The hermetic compressor according to claim 7, wherein the other parts are added for a purpose other than scattering the lubricating oil.

10. 8. The hermetic compressor of claim 7, wherein said portion is protruded in the shape of a spout.

11. The hermetic compressor according to claim 7 , wherein the portion is a V-shaped notch in a part of the other component.

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