JP2012052494A - Hermetically sealed compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hermetically sealed compressor that prevents galling, abrasion, etc due to contact of a crankshaft with the inside of a bearing portion, thereby improving reliability.SOLUTION: The hermetically sealed compressor includes: an electric motor part; a compression mechanism part 2 driven by the electric motor part; and a sealed container 1 housing the electric motor part and the compression mechanism part, and including an oil storage portion. The compression mechanism part includes a crankshaft 4 and a bearing portion, and formes a passage communicating the oil storage portion with the bearing portion in the crankshaft and a plurality of helical grooves communicating with the passage in an outer circumference of the crankshaft of the bearing portion. The configuration can provide an highly efficient hermetically sealed compressor that prevents the galling, abrasion, etc due to contact of the crankshaft and with the inside of the bearing portion while decreasing shear resistance due to oil viscosity of the bearing portion.

Description

  The present invention relates to a hermetic compressor used in a cooling apparatus such as an air conditioning / air conditioning apparatus or a refrigerator, or a heat pump type hot water supply apparatus.

  Conventionally, a case where a reciprocating compressor is employed as a hermetic compressor used in this type of refrigeration air conditioner or refrigerator will be considered. In the reciprocating compressor, an electric motor unit including a stator and a rotor is disposed in a hermetic container, and a compression mechanism unit is disposed on the motor unit.

  A crankshaft is inserted into a bearing portion of a block constituting the compression mechanism portion, a rotor is fixed to an outer diameter portion of the crankshaft, and is engaged with a slider of the piston via an eccentric shaft. Inside the crankshaft, there is formed a centrifugal pump that opens to the oil at the lower end.

  FIG. 4 shows a detailed view of a bearing portion in the prior art. A portion of the crankshaft located in the bearing portion is engraved with a spiral groove having a lead in a direction in which oil is guided upward when the crankshaft rotates forward.

  Further, the load generated by compressing the refrigerant is supported by the oil film pressure generated at the bearing upper portion and the bearing lower portion, and the crankshaft and the bearing portion are kept in non-contact. Since no oil film pressure is generated at the center of the bearing, the bearing shaft is widened by reducing the diameter of the crankshaft at the center of the bearing in the crankshaft, reducing shear resistance due to oil viscosity and increasing efficiency. Techniques for achieving this are generally known.

Yasutaka Ito and two others, “Lubrication analysis of bearings for reciprocating compressors (effect of oiling groove)”, 19-22 May 2005, Proceedings of the 2005 Annual Meeting of the Japan Society of Mechanical Engineers

  However, in the conventional configuration, since the bearing gap at the center portion in the bearing is wide, the oil flowing through the spiral groove once stays. In particular, at the time of start-up when the operating conditions change drastically, the refrigerant dissolved in the oil accumulated in the bearing may foam and the oil viscosity may decrease, but the oil film pressure generated at the top and bottom of the bearing at that time Decreases. As a result, the crankshaft and the bearing portion were in contact with each other, and there were problems in reliability such as galling and wear.

  The present invention solves the above-mentioned conventional problems, and reduces the shear resistance due to the viscosity of the oil in the bearing part, while preventing the galling and wear due to contact between the crankshaft and the inside of the bearing part. The purpose is to provide a machine.

In order to solve the conventional problems, a hermetic compressor according to the present invention houses an electric motor unit, a compression mechanism unit driven by the electric motor unit, the electric motor unit and the compression mechanism unit, and an oil And the compression mechanism includes a crankshaft and a bearing that pivotally supports the crankshaft, and the oil reservoir and the bearing communicate with the crankshaft. And a plurality of spiral grooves communicating with the passage are formed on the outer peripheral surface of the crankshaft of the bearing portion. As a result, a high-efficiency hermetic compressor that prevents galling and wear due to contact between the crankshaft and the bearing portion while reducing shear resistance due to the viscosity of the oil in the bearing portion is obtained.

  The hermetic compressor according to the present invention particularly has a compression mechanism portion that meshes with a fixed scroll and a turning scroll in which a spiral wrap rises from an end plate to form a compression chamber therebetween, and the turning scroll is controlled by a rotation restraint mechanism. By rotating along the circular orbit with a predetermined turning radius, the compression chamber moves toward the center while changing the volume, sucks the working fluid from the suction chamber formed in the fixed scroll, and performs a series of compression and discharge High efficiency can be realized when the scroll compression mechanism unit that performs the above operation is used.

Sectional drawing of the hermetic compressor in an embodiment of the present invention The principal part expanded sectional view of the compression mechanism part of the hermetic type compressor in an embodiment of the invention. The external view which expanded the principal part of the crankshaft of the hermetic compressor in embodiment of this invention Detailed view of bearing in conventional technology

  The first invention includes an electric motor unit, a compression mechanism unit driven by the electric motor unit, a sealed container having an oil storage unit and containing the electric motor unit and the compression mechanism unit, and the compression unit The mechanism portion includes a crankshaft and a bearing portion that supports the crankshaft, a passage that communicates the oil storage portion and the bearing portion with the crankshaft, and a plurality of spiral grooves that communicate with the passage. Is formed on the outer peripheral surface of the crankshaft of the bearing portion.

  As a result, by forming a plurality of spiral grooves, the area where the bearing gap is wide is expanded, the shear resistance due to the viscosity of the oil is reduced, and at the start of operation when the operation conditions change drastically, the oil is supplied by the lead. Since it can be discharged smoothly without being retained, it is possible to prevent a decrease in oil film pressure due to a decrease in oil viscosity due to foaming of the melted refrigerant.

  As a result, it is possible to provide a highly efficient hermetic compressor that prevents galling and wear due to contact between the crankshaft and the bearing portion.

  In the second invention, in particular, the plurality of spiral grooves of the first invention are independently formed without overlapping. According to this configuration, since oil can be discharged more smoothly, a more efficient hermetic compressor can be provided.

  In the third invention, in particular, the interval between the spiral grooves of the first or second invention is formed smaller than the width of the spiral groove. As a result, the region where the bearing gap is wide can be further expanded, so that a highly efficient hermetic compressor can be provided.

  In a fourth aspect of the invention, in particular, the compression mechanism portion of any one of the first to third aspects of the present invention is formed by engaging a fixed scroll and a turning scroll where a spiral wrap rises from the end plate to form a compression chamber therebetween. The orbiting scroll revolves with a predetermined orbiting radius along the circular orbit by the restriction by the rotation restraining mechanism, so that the compression chamber moves toward the center while changing the volume, and from the suction chamber formed in the fixed scroll. This is a scroll compression mechanism that sucks a working fluid and performs a series of operations of compression and discharge.

  As a result, there are two or more bearing portions while realizing low noise and low vibration, which is a feature of the scroll compression mechanism portion. By forming a plurality of spiral grooves for each bearing portion, the bearing portion Therefore, it is possible to provide a highly efficient hermetic compressor in which the shear resistance due to the viscosity of the oil is reduced, and galling and wear due to contact between the crankshaft and the bearing portion are prevented.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a longitudinal sectional view of a hermetic compressor according to an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of a main part of a compression mechanism portion of the hermetic compressor according to an embodiment of the present invention.

  Hereinafter, the operation and action of the hermetic compressor will be described.

  As shown in FIGS. 1 and 2, a scroll compressor is taken as an example of the hermetic compressor of the present invention, and a scroll compression mechanism is adopted as the compression mechanism 2, and welding or shrink fitting is performed in the sealed container 1. A scroll type compression mechanism 2 is configured by sandwiching a turning scroll 13 meshing with the fixed scroll 12 between the main bearing member 11 of the fixed crankshaft 4 and the fixed scroll 12 bolted on the main bearing member 11. A rotation restraining mechanism 14 such as an Oldham ring that guides the orbiting scroll 13 to rotate in a circular orbit while preventing the rotation of the orbiting scroll 13 is provided between the orbiting scroll 13 and the main bearing member 11. The orbiting scroll 13 is eccentrically driven by the eccentric shaft portion 4a to cause the orbiting scroll 13 to move in a circular orbit, whereby the fixed scroll 12 and the orbiting scroll are moved. By utilizing the fact that the compression chamber 15 formed between the outer peripheral side and the control chamber 13 becomes smaller while moving from the outer peripheral side to the central portion, Refrigerant gas is sucked in from the suction chamber 17 and compressed, and the refrigerant gas having a predetermined pressure or more is discharged into the sealed container 1 by pushing the reed valve 19 from the discharge port 18 at the center of the fixed scroll 12. repeat.

  In addition, a high pressure region 30 and a back pressure chamber 29 set to a high pressure and a low pressure are formed on the back surface 13e of the orbiting scroll 13. By applying pressure on the back surface 13e, the orbiting scroll 13 is stably pressed against the fixed scroll 12, and leakage can be reduced and the circular orbit motion can be stably performed.

  During operation of the compressor, a pump 25 is provided at the lower end of the crankshaft 4 and is driven simultaneously with the scroll compressor. As a result, the pump 25 sucks up the oil 6 in the oil reservoir 20 provided at the bottom of the hermetic container 1 and removes foreign matter with an oil filter or the like, and then passes through the oil supply hole 26 running vertically through the crankshaft 4. The compression mechanism unit 2 is supplied.

  The supply pressure at this time is substantially equal to the discharge pressure of the scroll compressor, and also serves as a back pressure source for the orbiting scroll 13. As a result, the orbiting scroll 13 does not move away from the fixed scroll 12 and does not come into contact with each other, and the predetermined compression function is stably exhibited.

  Part of the oil 6 supplied in this way enters the fitting portion between the eccentric shaft portion 4a and the orbiting scroll 13 and the bearing portion 66 between the crankshaft 4 and the main bearing member 11 due to the supply pressure and its own weight. Then, the respective parts are lubricated and dropped, and the oil sump 20 is returned.

Further, the orbiting scroll 13 is formed with a path 55 having one opening end 55 a in the back pressure chamber 29 and the other opening end 55 b on the wrap upper surface 13 c of the orbiting scroll 13. By intermittently opening the other opening end 55b of the path 55 in the two recesses 12d and 12e formed in the lap bottom surface 12c of the fixed scroll 12, the first and second paths can be intermittently communicated. is doing.

  That is, the 1st path | route which the outer side compression chamber 15a formed in the lap | wrap outer side of the turning scroll 13 and the back pressure chamber 29 communicates is formed, and it passes along a 1st path | route from the back pressure chamber 29 to the outer side compression chamber 15a. And oil is supplied.

  Further, a second path is formed in which the inner compression chamber 15b formed inside the wrap of the orbiting scroll 13 and the back pressure chamber 29 communicate with each other, and the second pressure path 29 passes from the back pressure chamber 29 to the inner compression chamber 15b. And oil is supplied.

  From the above, the oil 6 in the back pressure chamber 29 is guided to the compression chamber 15 through the first and second paths, and leakage during compression can be prevented.

  The orbiting scroll 13 is formed with a third path 56 having one opening end 56 a in the high pressure region 30 and the other opening end 56 b on the wrap upper surface 13 c of the orbiting scroll 13. The other opening end 56 b opens continuously to the suction chamber 17, and the oil 6 is supplied from the high pressure region 30 to the suction chamber 17.

  The supplied oil 6 is sucked together with the refrigerant gas almost uniformly into both the outer compression chamber 15a formed outside the wrap of the orbiting scroll 13 and the inner compression chamber 15b formed inside the wrap, and compressed by the seal. Prevents leaks along the way.

  On the other hand, in the present embodiment, the fourth path 54 that communicates the high pressure region 30 and the back pressure chamber 29 will be described. A part of the oil 6 supplied to the high pressure region 30 passes through a fourth path 54 formed in the orbiting scroll 13 and having one open end in the high pressure region 30. Along with entering the pressure chamber 29 and lubricating the thrust sliding portion and the sliding portion of the rotation restraining mechanism 14, the back pressure of the orbiting scroll 13 is applied in the back pressure chamber 29.

  The amount of oil in the back pressure chamber 29 is compressed from the oil 6 entering the back pressure chamber 29 from the high pressure region 30 via the fourth path 54 and from the back pressure chamber 29 via the first and second paths. With respect to the oil 6 entering the chamber 15, when the former oil amount is large, excessive oil 6 is supplied to the back pressure chamber 29, so that the pressure in the back pressure chamber 29 increases.

  As a result, excessive back pressure is applied to the orbiting scroll 13. When an excessive back pressure is applied, the thrust load increases, which causes a problem of causing performance deterioration and reliability deterioration.

  Therefore, in the scroll compressor according to the present embodiment, a fourth path 54 is provided to control the oil 6 flowing into the back pressure chamber 29. Further, the sealing member 78 is disposed on the back surface 13 e of the orbiting scroll 13, so that the high pressure region 30 and the back pressure chamber 29 are partitioned.

  Thus, leakage of pressure from the high pressure region 30 to the back pressure chamber 29 can be prevented, so that oil inflow into the back pressure chamber 29 can be controlled only by the fourth path 54.

Note that, as a method of maintaining the inside of the back pressure chamber 29 at a constant intermediate pressure, the use of a back pressure adjustment mechanism has the same effect (not shown). The back pressure adjusting mechanism is a valve provided in a passage communicating from the back pressure chamber 29 through the inside of the fixed scroll 12 to the suction port 17, and the pressure in the back pressure chamber 29 is higher than the set pressure. Then, the valve is opened, and the oil in the back pressure chamber 29 is supplied to the suction port 17 to maintain the back pressure chamber at a constant intermediate pressure.

  FIG. 3 shows an enlarged external view of the main part of the crankshaft 4. The oil 6 that has reached the upper part of the crankshaft 4 through the oil supply hole 26 running vertically through the crankshaft 4 is divided into one that is supplied to the compression mechanism portion 2 and one that is supplied to the bearing portion 66. A plurality of spiral grooves 100a and 100b are formed in the eccentric shaft portion 4a and the main bearing portion 4b, respectively.

  The oil 6 lubricates the bearing portion 66 formed at the fitting portion between the eccentric shaft portion 4 a and the orbiting scroll 13 by the plurality of spiral grooves 100 a formed on the eccentric shaft portion 4 a, and then the oil 6 enters the high pressure region 30. Is supplied.

  Thereafter, the oil 6 is lubricated to the bearing portion 66 between the main bearing portion 4b and the main bearing member 11 by the plurality of spiral grooves 100b provided in the main bearing portion 4b, and then drops, and returns to the oil reservoir 20.

  Next, the reason why a plurality of spiral grooves 100a and 100b are formed will be described. Generally known is a method of forming a wide bearing gap, reducing shear resistance due to oil viscosity, and improving efficiency. Therefore, by forming the plurality of spiral grooves 100a and 100b, it is possible to enlarge a region where the bearing gap is wide and reduce shear resistance due to oil viscosity.

  On the other hand, even with a single spiral groove, it is possible to enlarge a region where the bearing gap is wide by widening the groove width. However, when the groove width is widened with one spiral groove, a secondary flow of oil 6 (flow in a direction perpendicular to the flow along the groove) is generated in the groove, and the oil 6 is smoothly discharged from the bearing portion 66. Not.

  In order to discharge the oil 6 smoothly, it is necessary to increase the number of turns of the spiral groove (or the angle of the lead). In this case, the spiral groove is formed even in the region where the load of the crankshaft 4 acts. As a result, the oil film pressure generated at the upper part of the bearing and the lower part of the bearing is lowered, and the crankshaft 4 and the bearing part 66 are brought into contact with each other.

  However, by forming a plurality of spiral grooves 100a and 100b, the region where the bearing gap is widened is enlarged, the shear resistance due to the viscosity of the oil is reduced, and at the start of operation where the operation conditions change drastically, the lead Since the oil 6 can be smoothly discharged without stagnation, it is possible to minimize a decrease in the oil film pressure due to the melted refrigerant foaming and the oil viscosity decreasing.

  As a result, it is possible to provide a highly efficient hermetic compressor that prevents galling and wear due to contact between the crankshaft 4 and the bearing portion 66.

  In the present embodiment, two spiral grooves are used, but the same effect can be obtained even if two or more spiral grooves are formed (not shown).

  In the embodiment of the present invention, the plurality of spiral grooves 100a and 100b are independently formed without overlapping. With this configuration, since the oil 6 flowing in the spiral groove does not collide with each other, the oil 6 can be discharged more smoothly, so that a highly efficient hermetic compressor can be provided.

In addition, the space | interval of spiral grooves is formed smaller than the width | variety of a spiral groove. According to this configuration, the spiral groove is prevented from extending to the region where the load of the crankshaft 4 acts, and as a result, the region where the bearing gap is wider can be further increased without reducing the oil film pressure generated at the bearing upper portion and the bearing lower portion. Since it can expand, a more efficient hermetic compressor can be provided.

  In the embodiment of the present invention, the compression mechanism unit 2 is a scroll compression mechanism unit, but it can be similarly applied to other compressors such as a rotary compressor and a reciprocating compressor. In particular, when the compression mechanism portion 2 is a scroll compression mechanism portion, there are two or more bearing portions 66. Therefore, by forming a plurality of spiral grooves on each bearing portion 66, the oil 6 of the bearing portion 66 is reduced. It is possible to provide a more efficient hermetic compressor that reduces shear resistance due to viscosity and prevents galling and wear due to contact between the crankshaft 4 and the bearing portion 66.

  As described above, the hermetic compressor according to the present invention houses an electric motor unit, a compression mechanism unit driven by the electric motor unit, the electric motor unit and the compression mechanism unit, and an oil storage unit. An airtight container, and the compression mechanism portion includes a crankshaft and a bearing portion that pivotally supports the crankshaft, and a passage that communicates the oil storage portion and the bearing portion with the crankshaft. A plurality of spiral grooves communicating with the passage are formed on the outer peripheral surface of the crankshaft of the bearing portion. According to this configuration, it is possible to provide a highly efficient hermetic compressor that prevents galling and wear due to contact between the crankshaft and the bearing portion while reducing shear resistance due to oil viscosity of the bearing portion. Therefore, the working fluid is not limited to the refrigerant, and can be applied to a fluid compressor including a hermetic compressor using air or helium as a working fluid or an expander.

DESCRIPTION OF SYMBOLS 2 Compression mechanism part 11 Main bearing member 12 Fixed scroll 12b Lap groove 12c Lap bottom surface 13 Orbiting scroll 13c Lap top surface 13e Back surface 14 Rotation restraint mechanism 15 Compression chamber 15a Outer compression chamber 15b Inner compression chamber 16 Suction pipe 16a Outer tube 16b Heat insulation layer 16c Inner tube 29 Back pressure chamber 30 High pressure region 66 Bearing portion 100a, 100b Spiral groove

Claims (4)

An electric motor unit; a compression mechanism unit driven by the electric motor unit; and a sealed container that houses the electric motor unit and the compression mechanism unit and includes an oil storage unit, the compression mechanism unit including a crankshaft And a bearing that pivotally supports the crankshaft, a passage that communicates the oil storage portion and the bearing with the crankshaft, and a plurality of spiral grooves that communicate with the passage. A hermetic compressor formed on an outer peripheral surface of the crankshaft. The hermetic compressor according to claim 1, wherein the plurality of spiral grooves are independently formed without overlapping. The hermetic compressor according to claim 1 or 2, wherein an interval between the spiral grooves is smaller than a width of the spiral grooves. A compression chamber is formed between the compression mechanism portion by engaging a fixed scroll and a turning scroll in which a spiral wrap rises from the end plate, and the turning scroll is swung along a circular orbit by regulation by a rotation restraint mechanism. A scroll compression mechanism that performs a series of operations of compression and discharge by revolving around a radius so that the compression chamber moves toward the center while changing the volume and sucks the working fluid from the suction chamber formed in the fixed scroll. The hermetic compressor according to any one of claims 1 to 3, wherein the hermetic compressor is a part.