DESCRIPTION
Title of Invention HERMETIC COMPRESSOR Technical Field [0001]
The present invention relates to a hermetic compressor used in a refrigerating and air-conditioning apparatus. Background Art [0002]
A conventional hermetic compressor comprises a compression mechanism unit that compresses refrigerant and an electric motor mechanism unit that drives the compression mechanism unit, and the compression mechanism unit and the electric motor mechanism unit are stored in a sealed container. The compression mechanism unit and the electric motor mechanism unit are connected together by a crankshaft, and the electric motor mechanism unit drives the compression mechanism unit. The compression mechanism unit has a compression chamber to suction the refrigerant from a suction port, compress the refrigerant, and discharge the refrigerant from a discharge port.
The crankshaft comprises a main shaft portion, an eccentric shaft portion, and a sub-shaft portion, and a rolling piston is fitted around the eccentric shaft portion of the crankshaft. The compression mechanism unit is formed of a cylinder, the roiling piston, and shaft bearings. The cylinder has a cylinder chamber, which is an internal space of the cylinder and stores the eccentric shaft portion of the crankshaft and the rolling piston. An outer circumferential surface of the rolling piston corresponding to the outer diameter thereof and an inner circumferential surface of the cylinder chamber of the cylinder corresponding to the inner diameter thereof form an operation chamber. The crankshaft is rotated by the electric motor mechanism unit, and the eccentric shaft portion is also rotated eccentrically. The rolling piston fitted around the eccentric shaft portion eccentrically rotates in the cylinder chamber of the cylinder. With the eccentric rotation of the rolling piston, the operation chamber formed by the

cylinder and the rolling piston changes the volume thereof to compress the refrigerant suctioned into the operation chamber.
The shaft bearings are attached to the cylinder, and support the crankshaft. [0003]
Due to the above-described configuration, the compression mechanism unit has many sliding parts, and thus requires lubricating oil. Further, gaps between components need to be sealed to suppress the leakage of the refrigerant from the compression chamber. [0004]
A bottom portion of the sealed container stores refrigerating machine oil for lubricating the sliding parts of the compression mechanism unit and sealing the compression chamber. A lower portion of the crankshaft is immersed in the refrigerating machine oil in an oil reservoir. With the centrifugal pumping action due to the rotation of the crankshaft, the refrigerating machine oi! is pumped up into an oil feed passage formed inside the crankshaft, and is supplied to the sliding parts of the compression mechanism unit via the oil feed passage. For example, the crankshaft has shaft bearing oil feed holes and a rolling piston oi! feed hole for supplying the refrigerating machine oil to the shaft bearings and the roiling piston, respectively, from the oil feed passage of the crankshaft. Thereby, the refrigerating machine oil is supplied to the sliding parts, such as the rolling piston, the crankshaft, and the shaft bearings, and sealing areas of the components. There is also a configuration having oil feed holes for supplying the refrigerating machine oil to spaces divided by the rolling piston, the shaft bearings, and the crankshaft or to upper and lower end surfaces, that is, thrust surfaces, of the eccentric shaft portion of the crankshaft (see Patent Literature 1 and 2, for example). Citation List Patent Literature [0005]
Patent Literature 1: Japanese Unexamined Patent Application Publication No. 61-055391 (Page 3 and Fig. 1)

Patent Literature 2: Japanese Unexamined Utility Model Registration Application Publication No. 02-076190 (Page 4 and Figs. 1 and 2) Summary of Invention Technical Problem [0006]
To manufacture a small, high-output air-conditioning apparatus, the hermetic compressor also needs to have a small exterior and a large refrigerant compression volume, that is, a large excluded volume. For a reduction in size and an increase in volume of the hermetic compressor, however, it is necessary to increase the excluded volume while maintaining the height and the inner diameter of the cylinder, and an increase in the eccentricity amount of the eccentric shaft portion of the crankshaft is required therefor. To increase the eccentricity amount while maintaining the inner diameter of the cylinder, it is necessary to increase the diameter of the eccentric shaft and reduce the outer diameter of the rolling piston. [0007]
The increase in diameter of the eccentric shaft and the reduction in outer diameter of the rolling piston, on the other hand, results in a reduction in thickness in the radial direction of the rolling piston. Thus, the amount of the refrigerating machine oil retained between end surfaces in the axial direction of the rolling piston and components of the compression mechanism unit is reduced, reducing the retention force and degrading the lubrication performance and the sealing performance. Further, in each of the existing oil feed holes, the increase of the eccentricity amount increases the distance from an opening of the oil feed hole to an end surface in the eccentric direction of the eccentric shaft portion, making the distribution of the refrigerating machine oil difficult. Thus, oil feeding is discontinued, and the lubrication performance and the sealing performance are degraded. [0008]
Further, even if the number of oil feed holes in the radial direction is increased to prevent the discontinuation of oil feeding, the repulsive force of the compressed refrigerant acting toward the center of the crankshaft from the operation chamber

hinders flows of the refrigerating machine oil through the oil feed holes in the radial direction, raising an issue of difficulty in discharging the refrigerating machine oil from the oil feed holes. [0009]
If the eccentricity amount of the hermetic compressor is increased, therefore, the lubrication performance of lubricating the compression mechanism unit deteriorates, increasing a sliding loss. In addition, the sealing performance of sealing the rolling piston deteriorates, allowing the refrigerant in the compression chamber to leak from a high-pressure side to a low-pressure side, and reducing the volumetric efficiency of the compressor. In some cases, therefore, the energy saving performance of an entire cooling energy system employing this compressor is degraded. [0010]
The present invention has been made to overcome issues as described above, and provides a hermetic compressor in which the eccentricity amount of the eccentric shaft portion of the crankshaft is increased to increase the excluded volume while the height and the inner diameter of the cylinder are maintained, and which has oil feed passages through which the refrigerating machine oil is continuously supplied to the outer circumferential surface in the radial direction of the eccentric shaft portion and the outer circumferential surface of the rolling piston irrespective of the increase in the eccentricity amount of the eccentric shaft portion of the crankshaft, thereby ensuring the lubrication performance of lubricating the sliding parts of the compression mechanism unit to suppress the abrasion of the sliding parts, and maintaining the sealing performance of sealing the compression mechanism unit to reduce the leakage loss of the compression chamber. Solution to Problem [0011]
A hermetic compressor according to an embodiment of the present invention includes a sealed container storing refrigerating machine oil, the hermetic compressor housing a compression mechanism unit, the compression mechanism unit

comprising: a crankshaft having an oil feed passage through which the refrigerating machine oil is suctioned up and an eccentric shaft portion; a cylinder housing the eccentric shaft portion and having a cylinder chamber; shaft bearings that close the cylinder chamber and support the crankshaft; and a cylindrical piston attached to the eccentric shaft portion, and the eccentric shaft portion having a first oii feed hole communicating with the oii feed passage of the crankshaft, and having an opening in an outer circumferential surface in an eccentric direction of the eccentric shaft portion, and a second oil feed hole communicating with the first oil feed hole, and having an opening in an outer circumferential surface in an axial direction of the eccentric shaft portion.
Advantageous Effects of Invention [0012]
In the hermetic compressor according to an embodiment of the present invention, the eccentric shaft portion of the crankshaft has the oil feed hole in the eccentric direction, which communicates with the oil feed passage of the crankshaft and has the opening in the outer circumferential surface in the eccentric direction of the eccentric shaft portion, and the oil feed hole in the axial direction, which communicates with the oil feed hole in the eccentric direction and has the opening in the outer circumferential surface in the axial direction of the eccentric shaft portion. It is therefore possible to obtain a hermetic compressor that continuously supplies the refrigerating machine oil to the outer circumferential surface in the radial direction of the eccentric shaft portion and the outer circumferential surface of the roiling piston, even if the eccentricity amount of the eccentric shaft portion of the crankshaft is increased while the height and the inner diameter of the cylinder are maintained, thereby ensuring the lubrication performance of lubricating the sliding parts of the compression mechanism unit to suppress the abrasion of the sliding parts, and maintaining the sealing performance of sealing the compression mechanism unit to reduce the leakage loss of the compression chamber. Brief Description of Drawings

[0013]
[Fig. 1] Fig. 1 is an illustrative diagram of the entirety of a hermetic compressor in Embodiment 1 of the present invention.
[Fig. 2] Fig. 2 is an enlarged view of a compression mechanism unit of the hermetic compressor in Embodiment 1 of the present invention.
[Fig. 3] Fig. 3 is an illustrative diagram of the compression mechanism unit of the hermetic compressor in Embodiment 1 of the present invention, with the compression mechanism unit viewed in the axial direction thereof.
[Fig. 4] Fig. 4 is an enlarged view of the exterior of a crankshaft in Embodiment 1 of the present invention.
[Fig. 5] Fig. 5 is an external view of the crankshaft in Embodiment 1 of the present invention, with the crankshaft viewed from the side of a sub-shaft portion.
[Fig. 6] Fig. 6 is a diagram illustrating directions of the crankshaft in Embodiment 1 of the present invention.
[Fig. 7] Fig. 7 is an illustrative diagram of a refrigerant circuit employing the hermetic compressor in Embodiment 1 of the present invention.
[Fig. 8] Fig. 8 is an illustrative diagram of an operation of the compression mechanism unit of the hermetic compressor in Embodiment 1 of the present invention.
[Fig. 9] Fig. 9 is a diagram illustrating a main shaft portion, the sub-shaft portion, and an eccentric shaft portion of the crankshaft in Embodiment 1 of the present invention.
[Fig. 10] Fig. 10 is an illustrative diagram in which an eccentricity amount of the eccentric shaft portion of the crankshaft in Embodiment 1 of the present invention is increased.
[Fig. 11] Fig. 11 is an illustrative diagram of the crankshaft in Embodiment 1 of the present invention having an oil feed hole in an eccentric direction, with the crankshaft viewed from the side of the sub-shaft.

[Fig. 12] Fig. 12 is an illustrative diagram of the crankshaft in Embodiment 1 of the present invention having the oil feed hole in the eccentric direction, with the crankshaft viewed in the radial direction thereof.
[Fig. 13] Fig. 13 is an illustrative diagram of oil feed holes in the eccentric direction of the crankshaft in Embodiment 1 of the present invention.
[Fig. 14] Fig. 14 is an external view of the crankshaft in Embodiment 1 of the present invention, with the crankshaft viewed from the side of the sub-shaft portion.
[Fig. 15] Fig. 15 is a sectional view of the crankshaft in Embodiment 1 of the present invention.
[Fig. 16] Fig. 16 is a diagram illustrating flows of refrigerating machine oil through oil feed holes of the crankshaft in Embodiment 1 of the present invention. Description of Embodiments [0014] Embodiment 1
Fig. 1 is an illustrative longitudinal view illustrating a hermetic rotary compressor in Embodiment 1 for implementing the present invention, that is, the hermetic rotary compressor viewed in the radial direction of a crankshaft. Fig. 2 is an enlarged view of a compression mechanism unit in Fig. 1. Fig. 3 is a view of a section taken along X-X' in Fig. 1, that is, along a plane perpendicular to the axial direction of the crankshaft, and viewed in the axial direction, that is, an illustrative diagram of the compression mechanism unit as viewed from above. [0015]
As illustrated in Fig. 1, a hermetic compressor 100 has a sealed container 1 housing therein a compression mechanism unit 3 and an electric motor mechanism unit 2 above the compression mechanism unit 3. The electric motor mechanism unit 2 and the compression mechanism unit 3 are connected together by a crankshaft 4. The electric motor mechanism unit 2 is formed of a stator 21 and a rotator 22 that is rotated by magnetic force generated by the stator 21. The crankshaft 4 transmits rotational force of the electric motor mechanism unit 2 to the compression mechanism unit 3. The stator 21 includes a coil of a wound conducting wire, and generates the

magnetic force with power supplied to the coil. The coil of the stator 21 is connected to a terminal 23 provided to the hermetic compressor 100, and is supplied with power from the outside of the hermetic compressor 100 via the terminal 23. The rotator 22 includes components such as a secondary conductor formed of an aluminum bar and a permanent magnet, and rotates in response to the magnetic force generated by the coi! of the stator 21. [0016]
With the transmitted rotational force of the electric motor mechanism unit 2, the compression mechanism unit 3 compresses low-pressure refrigerant gas suctioned therein, and discharges high-pressure refrigerant gas into the sealed container 1. The interior of the sealed container 1 is filled with compressed high-temperature, high-pressure refrigerant gas. Meanwhile, a lower portion, that is, a bottom portion of the sealed container 1 stores refrigerating machine oil for lubricating the compression mechanism unit 3. [0017]
The crankshaft 4 is formed of a main shaft portion 41, a sub-shaft portion 42, and an eccentric shaft portion 43, which are arranged in the order of the main shaft portion 41, the eccentric shaft portion 43, and the sub-shaft portion 42 in the axial direction. That is, the main shaft portion 41 is provided on one side in the axial direction of the eccentric shaft portion 43, and the sub-shaft portion 42 is provided on the other side in the axial direction of the eccentric shaft portion 43. The main shaft portion 41, the sub-shaft portion 42, and the eccentric shaft portion 43 each have a substantially cylindrical shape, and are provided such that the axial center of the main shaft portion 41 and the axial center of the sub-shaft portion 42 match, that is, the main shaft portion 41 and the sub-shaft portion 42 are coaxial. The eccentric shaft portion 43, on the other hand, is provided such that the axial center thereof is off the axial center of the main shaft portion 41 and the sub-shaft portion 42. When the main shaft portion 41 and the sub-shaft portion 42 rotate around the axial center thereof, the eccentric shaft portion 43 eccentrically rotates. The rotator 22 of the electric motor mechanism unit 2 is shrink-fitted or press-fitted around the main shaft

portion 41 to be fixed thereto, and a cylindrical rolling piston 32 is slidably attached to
the eccentric shaft portion 43.
[0018]
As illustrated in the enlarged view of the crankshaft 4 in Fig. 4, an outer circumferential surface in the radial direction of the eccentric shaft portion 43 is provided with a band-shaped projecting portion 44, which surrounds the circumference of the eccentric shaft portion 43 and projects from the eccentric shaft portion 43. Further, the rolling piston 32 is fitted with a clearance of tens of microns formed between an inner circumferential surface of the rolling piston 32 corresponding to the inner diameter thereof and an outer circumferential surface A in the radial direction of the projecting portion 44. In outer circumferential surfaces in the radial direction of the eccentric shaft portion 43, an outer circumferential surface B and an outer circumferential surface C as non-projecting portions, on the other hand, do not come in contact with the rolling piston 32, with a gap corresponding to a clearance of a few millimeters formed between each of the outer circumferential surfaces B and C and the inner circumferential surface of the rolling piston 32 corresponding to the inner diameter thereof. That is, the outer circumferential surface A is a sliding surface, while each of the outer circumferential surfaces B and C is a non-sliding surface. This configuration reduces the area of sliding movement between the rolling piston 32 and the eccentric shaft portion 43, and thus is capable of reducing friction and a sliding loss. Although the projecting portion 44 in Fig. 2 has the band shape surrounding the circumference of the eccentric shaft portion 43, the projecting portion 44 is not necessarily required to be provided around the circumference of the eccentric shaft portion 43 by 360 degrees, and is not necessarily required to have the band shape. A part of the projecting portion 44 may be cut out in the axial direction.
Further, although Fig. 4 illustrates an example in which the projecting portion 44 is provided to the eccentric shaft portion 43, a release portion or a projecting portion provided to the rolling piston 32 would also be capable of providing the sliding surface and the non-sliding surface to the inner circumferential surface of the rolling

piston 32 corresponding to the inner diameter thereof and the outer circumferential surface in the radial direction of the eccentric shaft portion 43, and also forming a gap corresponding to a clearance of a few millimeters between the inner circumferential surface of the rolling piston 32 corresponding to the inner diameter thereof and the outer circumferentia! surface in the radial direction of the eccentric shaft portion 43. [0019]
The crankshaft 4 has a hollow cylindrical hole provided at the axial center thereof. The hollow hole serves as an oil feed passage 45 for transporting the refrigerating machine oil in the bottom portion of the seated container 1. The oil feed passage 45 has an opening 46 in an end surface in the axial direction of the sub-shaft portion 42. A portion of the crankshaft 4 on the side of the sub-shaft portion 42 is immersed in the refrigerating machine oil stored in the bottom portion of the sealed container 1. The stored refrigerating machine oil is suctioned up through the oil feed passage 45 from the opening 46 of the sub-shaft portion 42 with a centrifugal pumping effect caused when the crankshaft 4 rotates and a differential pressure effect caused between a high-pressure space formed with the high-pressure refrigerant gas filling the sealed container 1 and a low-pressure space formed with the low-pressure refrigerant gas suctioned into the compression mechanism unit 3. The suctioned-up refrigerating machine oil is supplied to sliding parts of the compression mechanism unit 3. The sliding parts supplied with the refrigerating machine oil will be described later. [0020]
As illustrated in Figs. 2 and 3, the compression mechanism unit 3 is formed of a cylinder 31, the roiling piston 32, an upper shaft bearing 33, a lower shaft bearing 34, and a vane 35. The cylinder 31 has a cylindrical internal space, that is, a cylinder chamber 36, both ends in the axial direction of which are open. The cylinder chamber 36 of the cylinder 31 houses the eccentric shaft portion 43 of the crankshaft 4 and the rolling piston 32 attached to the eccentric shaft portion 43. Further, with the rotation of the crankshaft 4, the eccentric shaft portion 43, that is, the rolling piston 32, eccentrically rotates inside the cylinder chamber 36 of the cylinder 31.

[0021]
The cylinder 31 has a vane groove 37 in the radial direction of the cylinder chamber 36. The vane groove 37 has one side opening to the cylinder chamber 36 and the other side opening to a back pressure chamber 38. The vane groove 37 houses the vane 35, which has a substantially cuboidal shape and reciprocates while sltdingly moves in the vane groove 37. The back pressure chamber 38 includes a spring, which pushes the vane 35 into the cylinder chamber 36 of the cylinder 31 from the vane groove 37 to bring a leading end of the vane 35 into contact with the rolling piston 32. That is, the space formed by the inner circumferential surface of the cylinder chamber 36 of the cylinder 31 corresponding to the inner diameter of the cylinder chamber 36 and the outer circumferential surface of the roiling piston 32 corresponding to the outer diameter thereof is divided by the vane 35 into two operation chambers. [0022]
The upper shaft bearing 33, which closes one opening in the axial direction of the cylinder 31, that is, an upper opening of the cylinder chamber 36 of the cylinder 31, is bolt-fixed to an upper surface of the cylinder 31. That is, the upper shaft bearing 33 closes the upper side of the two operation chambers inside the cylinder 31. The upper shaft bearing 33 includes a flat plate-shaped fixing portion bolt-fixed to the cylinder 31 and a cylindrical shaft bearing portion extended from the fixing portion away from the cylinder 31, that is, toward the rotator 22. The shaft bearing portion has respective openings in both ends in the axial direction thereof, and a communication space allowing communication between the openings. The communication space of the shaft bearing portion supports the main shaft portion 41, which is inserted through the communication space from one of the openings to the other one of the openings. That is, the upper shaft bearing 33 supports the main shaft portion 41, that is, the crankshaft 4, to be rotatable in the radial direction. [0023]
Similarly, the lower shaft bearing 34, which closes the other opening in the axial direction of the cylinder 31, that is, a lower opening of the cylinder chamber 36 of the

cylinder 31, is bolt-fixed to a lower surface of the cylinder 31. That is, the lower shaft bearing 34 closes the lower side of the two operation chambers inside the cylinder 31. The lower shaft bearing 34 includes a flat plate-shaped fixing portion bolt-fixed to the cylinder 31 and a cylindrical shaft bearing portion extended from the fixing portion away from the cylinder 31, that is, toward the bottom portion of the sealed container 1. The shaft bearing portion has respective openings in both ends in the axial direction thereof, and a communication space allowing communication between the openings. The communication space of the shaft bearing portion supports the sub-shaft portion 42, which is inserted through the communication space from one of the openings to the other one of the openings. That is, the lower shaft bearing 34 supports the sub-shaft portion 42, that is, the crankshaft 4, to be rotatable in the radial direction. [0024]
As illustrated in Figs. 4 and 5, a lower surface, for example, of outer circumferential surfaces in the axial direction of the eccentric shaft portion 43 is formed of an outer circumferential surface D, which is a fiat surface of the eccentric shaft portion 43 perpendicular to the axial direction of the crankshaft 4, and an outer circumferential surface E, which is a flat surface inclined toward the main shaft portion 41 toward an outer circumferential surface in the radial direction and the eccentric direction of the eccentric shaft portion 43. Therefore, the eccentric shaft portion 43 slidingly moves between the outer circumferential surface D of the eccentric shaft portion 43 and a flat surface of the lower shaft bearing 34 on the side of the eccentric shaft portion 43. Meanwhile, the outer circumferential surface E and the flat surface of the lower shaft bearing 34 on the side of the eccentric shaft portion 43 do not come into contact with each other, and a space, that is, a gap is formed therebetween. That is, the outer circumferential surface D is a sliding surface, and the outer circumferential surface E is a non-sliding surface serving as a release portion of the eccentric shaft portion 43 on the side of the sub-shaft portion 42. This configuration reduces the area of sliding movement between the lower shaft bearing 34 and the eccentric shaft portion 43, and thus is capable of reducing the friction and the sliding

loss. The outer circumferential surface D and the outer circumferential surface E are divided by a reference line J, but are flat surfaces continuous with each other. The reference line J is provided in a circular arc shape, with the axial center of the crankshaft 4 as the start point thereof.
Although Figs. 4 and 5 illustrate an example in which the outer circumferential surface E of the eccentric shaft portion 43 is an inclined flat surface, another configuration may be adopted in which the flat surface of the lower shaft bearing 34 on the side of the eccentric shaft portion 43 has a release portion. Such a configuration is capable of providing the sliding surface and the non-sliding surface to the flat surface of the lower shaft bearing 34 on the side of the eccentric shaft portion 43 and the flat surface of the eccentric shaft potion 43 on the side of the lower shaft bearing 34, and forming a gap between the flat surface of the lower shaft bearing 34 on the side of the eccentric shaft portion 43 and the flat surface of the eccentric shaft potion 43 on the side of the lower shaft bearing 34.
Fig. 5 is a view of the crankshaft 4 in Fig. 4, as viewed from the side of the sub-shaft portion 42. [0025]
Further, as illustrated in Fig. 6, with reference to the axial center of the main shaft portion 41 and the sub-shaft portion 42 on a straight line connecting the axial center of the crankshaft 4, that is, the axial center of the main shaft portion 41 and the sub-shaft portion 42, and the axial center of the eccentric shaft portion 43, the eccentric direction corresponds to a range of ± 90 degrees in a direction from the axial center of the main shaft portion 41 and the sub-shaft portion 42 toward the axial center of the eccentric shaft portion 43. Therefore, with reference to the axial center of the main shaft portion 41 and the sub-shaft portion 42 on the straight line connecting the axial center of the main shaft portion 41 and the sub-shaft portion 42 and the axial center of the eccentric shaft portion 43, a counter-eccentric direction corresponds to a range of ± 90 degrees in a direction from the axial center of the eccentric shaft portion 43 toward the axial center of the main shaft portion 41 and the sub-shaft portion 42.

[0026]
Similarly, an upper surface of the outer circumferential surfaces in the axial direction of the eccentric shaft portion 43 is formed of an outer circumferential surface F, which is a flat surface of the eccentric shaft portion 43 perpendicular to the axial direction of the crankshaft 4, and an outer circumferential surface G, which is a flat surface inclined toward the sub-shaft portion 42 toward the outer circumferential surface in the radial direction and the eccentric direction of the eccentric shaft portion 43. Between the outer circumferential surface G and a flat surface of the upper shaft bearing 33 on the side of the eccentric shaft portion 43, a space, that is, a gap is formed which is larger than a space between the outer circumferential surface F and the flat surface of the upper shaft bearing 33 on the side of the eccentric shaft portion 43. Further, the gap serves as a release portion of the eccentric shaft portion 43 on the side of the main shaft portion 41. Although not illustrated, the outer circumferential surface F and the outer circumferential surface G, which are divided by a reference line K, are flat surfaces continuous with each other, similarly to that in Fig. 5. The reference line K is provided in a circular arc shape, with the axial center of the crankshaft 4 as the end point thereof.
Similarly to the lower surface, the upper surface of the outer circumferential surfaces in the axial direction of the eccentric shaft portion 43 has been described with an example in which the outer circumferential surface G of the eccentric shaft portion 43 is an inclined flat surface. However, another configuration may be adopted in which the flat surface of the upper shaft bearing 33 on the side of the eccentric shaft portion 43 has a release portion. Such a configuration is capable of providing the non-sliding surface to the flat surface of the upper shaft bearing 33 on the side of the eccentric shaft portion 43 and the flat surface of the eccentric shaft portion 43 on the side of the upper shaft bearing 33, and forming a gap between the flat surface of the upper shaft bearing 33 on the side of the eccentric shaft portion 43 and the flat surface of the eccentric shaft portion 43 on the side of the upper shaft bearing 33. [0027]

The cylinder 31 has a suction port through which the refrigerant gas is suctioned into the cylinder chamber 36 of the cylinder 31 from the outside of the sealed container 1, and which communicates with one of the operation chambers divided by the vane 35. Further, the upper shaft bearing 33 has a discharge port through which the compressed refrigerant gas is discharged to the outside of the cylinder chamber 36 of the cylinder 31, and which communicates with the other one of the operation chambers divided by the vane 35. [0028]
The discharge port of the upper shaft bearing 33 is provided with a discharge valve, which is closed until the refrigerant gas compressed in the corresponding operation chamber reaches a predetermined pressure, and opens when the refrigerant gas reaches or exceeds the predetermined pressure, to thereby discharge the high-temperature, high-pressure refrigerant gas into the sealed container 1. Thereby, the discharge timing of the refrigerant gas discharged from the cylinder 31 is controlled. [0029]
The refrigerant gas discharged into the sealed container 1 is delivered toward a discharge pipe 11 located at an upper part of the sealed container 1, and is delivered to the outside of the sealed container 1 from the discharge pipe 11. In this process, the refrigerant gas is delivered upward through a gap between the stator 21 and the rotator 22 of the electric motor mechanism unit 2 and a vent hole provided in the rotator 22. [0030]
The suction port is connected, via a suction connection pipe 12, to a suction muffler 101 provided outside the sealed container 1. A mixture of low-pressure refrigerant gas and liquid refrigerant is transported into the hermetic compressor 100 from an external circuit connected to the hermetic compressor 100. If the liquid refrigerant flows into the compression mechanism unit 3 and is compressed therein, the compression mechanism unit 3 may fail. The suction muffler 101 therefore

separates the liquid refrigerant and the refrigerant gas from each other, and only
delivers the refrigerant gas to the compression mechanism unit 3.
[0031]
As illustrated in Fig. 7, a condenser 102, an expansion valve 103, and an evaporator 104 are provided outside the hermetic compressor 100 to form a refrigeration circuit. That is, a circular circuit is formed in which the discharge pipe 11 of the hermetic compressor 100 is connected by pipes to the suction muffler 101 via the condenser 102, the expansion valve 103, and the evaporator 104. The refrigerant circulates through this circuit to exchange heat with a medium such as air or water in the condenser 102 and the evaporator 104, to thereby form a refrigeration cycle for transferring heat energy and realize a heat pump apparatus. A reference sign 105 represents a four-way vaive, which performs switching to reverse a normal circuiation route of the refrigerant. That is, a normal route through which the refrigerant discharged from the hermetic compressor 100 sequentially flows through the condenser 102, the expansion valve 103, the evaporator 104, and the suction muffler 101 and returns to the hermetic compressor 100 is switched by the four-way valve 105 such that the refrigerant discharged from the hermetic compressor 100 sequentially flows through the evaporator 104, the expansion valve 103, the condenser 102, and the suction muffler 101 and returns to the hermetic compressor 100. Thereby, the transmission of the heat energy is reversed to switch between cooling and heating. With the reversal of the normal route, the condenser 102 changes to an evaporator, and the evaporator 104 changes to a condenser. [0032]
An operation of the compression mechanism unit 3 will now be described. As illustrated in Fig. 8, the operation chamber communicating with the suction port first suctions the low-pressure refrigerant gas. The operation chamber having suctioned the low-pressure refrigerant gas from the suction port moves inside the cylinder 31 in accordance with the eccentric rotation of the rolling piston 32, that is, the eccentric shaft portion 43, and the communication of the operation chamber with the suction port is discontinued. With further eccentric rotation of the rolling piston 32, the

volume of the operation chamber is reduced to compress the suctioned refrigerant gas. Along with the eccentric rotation of the rolling piston 32, the operation chamber and the discharge port communicate with each other. When the operation chamber and the discharge port communicate with each other and the discharge valve closing the discharge port opens the discharge port, the high-pressure refrigerant gas in the operation chamber is discharged into the sealed container 1 via the discharge port. With further eccentric rotation of the rolling piston 32, the operation chamber is disconnected from the discharge port, and the operation chamber again communicates with the suction port. These series of operations are performed during one rotation of the rolling piston 32 inside the cylinder 31. When one of the two operation chambers is suctioning the refrigerant gas, the other operation chamber is performing an operation of discharging the refrigerant gas. Between the operation chambers across the vane 35, therefore, the operation chamber communicating with the suction port and suctioning the low-pressure refrigerant gas serves as a suction chamber having a low-pressure space, and the operation chamber communicating with the discharge port and discharging the high-pressure refrigerant gas serves as a compression chamber having a high-pressure space. The excluded volume of refrigerant of a compressor is determined by the volume of an operation chamber of a compression mechanism unit. [0033]
Due to the above-described configuration, the compression mechanism unit 3 includes many sliding parts, which are supplied with the refrigerating machine oil to ensure the lubrication performance of lubricating the sliding parts. Further, in the compression mechanism unit 3, gaps between components are sealed with the refrigerating machine oil to prevent leakage of the compressed refrigerant gas from a high-pressure side to a low-pressure side. The refrigerating machine oil is also supplied for this reason. [0034]
For example, as illustrated in Fig. 4, a sub-shaft portion 42 side of a connecting portion of the sub-shaft portion 42 and the eccentric shaft portion 43 of the crankshaft

4, that is, a portion of the outer circumferential surface of the sub-shaft portion 42 near the eccentric shaft portion 43, has an oii feed hole 47 opening in the eccentric direction of the eccentric shaft portion 43 and communicating with the oil feed passage 45. Through the oil feed hole 47, the refrigerating machine oil suctioned up into the oil feed passage 45 is supplied to between the sub-shaft portion 42, the eccentric shaft portion 43, and the lower shaft bearing 34. Thereby, an oil film is formed between the surface of the eccentric shaft portion 43 on the side of the lower shaft bearing 34 and the surface of the lower shaft bearing 34 on the side of the eccentric shaft portion 43, ensuring the sliding performance and the sealing performance. Further, an oil film is formed between the surface on the side of the lower shaft bearing 34 of the sub-shaft portion 42 and the surface on the side of the sub-shaft portion 42 of the lower shaft bearing 34, ensuring the sliding performance and the sealing performance. [0035]
Similarly, a main shaft portion 41 side of a connecting portion of the main shaft portion 41 and the eccentric shaft portion 43 of the crankshaft 4, that is, a portion of the outer circumferential surface of the main shaft portion 41 near the eccentric shaft portion 43, has an oil feed hole 48 opening in the eccentric direction of the eccentric shaft portion 43 and communicating with the oil feed passage 45. Through the oil feed hole 48, the refrigerating machine oil suctioned up into the oil feed passage 45 is supplied to between the main shaft portion 41, the eccentric shaft portion 43, and the upper shaft bearing 33. Thereby, an oil film is formed between the surface of the eccentric shaft portion 43 on the side of the upper shaft bearing 33 and the surface of the upper shaft bearing 33 on the side of the eccentric shaft portion 43, ensuring the sliding performance and the sealing performance. Further, an oil film is formed between the surface of the main shaft portion 41 on the side of the upper shaft bearing 33 and the surface of the upper shaft bearing 33 on the side of the main shaft portion 41, ensuring the sliding performance and the sealing performance. [0036]

Further, as illustrated in Fig. 5, a side of the eccentric shaft portion 43 opposite to an eccentric direction side thereof, that is, a counter-eccentric direction side of the eccentric shaft portion 43, has a cutout 49 cut out in the axial direction. Thus, a space is formed between the cutout 49 and the inner circumferential surface of the rolling piston 32 corresponding to the inner diameter thereof. The space has an oil feed hole 50 that opens to communicate with the oil feed passage 45. That is, the oil feed hole 50 has an opening 51 and an oil feed passage 52, and the opening 51 is provided in the cutout 49, that is, the outer circumferential surface in the counter-eccentric direction of the eccentric shaft portion 43. Through the oil feed hole 50, the refrigerating machine oil suctioned up into the oil feed passage 45 is fed to the space formed by the cutout 49, and the refrigerating machine oil stored in the space is supplied to between the eccentric shaft portion 43 and the rolling piston 32. This configuration forms an oil film between an end surface of the eccentric shaft portion 43 on the side of the rolling piston 32 and an end surface of the rolling piston 32 on the side of the eccentric shaft portion 43, and thus is capable of ensuring the sliding performance.
The cutout 49 is provided to prevent the inner circumferential surface of the rolling piston 32 corresponding to the inner diameter thereof from closing the oil feed hole 50 and obstructing the supply of the refrigerating machine oil. [0037]
Further, the space formed by the cutout 49 and the inner circumferential surface of the rolling piston 32 corresponding to the inner diameter thereof communicates with the space formed by the outer circumferential surface B of the eccentric shaft portion 43 and the inner circumferential surface of the rolling piston 32 corresponding to the inner diameter thereof and the space formed by the outer circumferential surface C of the eccentric shaft portion 43 and the inner circumferential surface of the rolling piston 32 corresponding to the inner diameter thereof. Thus, the refrigerating machine oil fed through the oil feed hole 50 is supplied up to the outer circumferential surfaces in the eccentric direction of the eccentric shaft portion 43 through these spaces.

[0038]
Further, the space formed by the outer circumferential surface B of the eccentric shaft portion 43 and the inner circumferential surface of the roiling piston 32 corresponding to the inner diameter thereof also communicates with the space formed by the outer circumferential surface E of the eccentric shaft portion 43 and the flat surface of the lower shaft bearing 34 on the side of the eccentric shaft portion 43. Therefore, the refrigerating machine oil fed through the oil feed hole 50 is also fed to the space formed by the outer circumferential surface E of the eccentric shaft portion 43 and the flat surface of the lower shaft bearing 34 on the side of the eccentric shaft portion 43. [0039]
Similarly, the space formed by the outer circumferential surface C of the eccentric shaft portion 43 and the inner circumferential surface of the rolling piston 32 corresponding to the inner diameter thereof also communicates with the space formed by the outer circumferential surface G of the eccentric shaft portion 43 and the flat surface of the upper shaft bearing 33 on the side of the eccentric shaft portion 43. Therefore, the refrigerating machine oil fed through the oil feed hole 50 is also fed to the space formed by the outer circumferential surface G of the eccentric shaft portion 43 and the flat surface of the upper shaft bearing 33 on the side of the eccentric shaft portion 43. [0040]
With the centrifugal force generated when the crankshaft 4 rotates, the refrigerating machine oi! supplied from the oil feed holes 47, 48, and 50 is transported to the rolling piston 32 farther than the outer circumferential surface in the radial direction of the eccentric shaft portion 43, and also flows into between the rolling piston 32 and the upper shaft bearing 33 and between the rolling piston 32 and the lower shaft bearing 34. This configuration forms an oil film between an end surface of the roiling piston 32 on the side of the upper shaft bearing 33 and an end surface of the upper shaft bearing 33 on the side of the eccentric shaft portion 43 and between an end surface of the rolling piston 32 on the side of the lower shaft bearing 34 and

an end surface of the lower shaft bearing 34 on the side of the eccentric shaft portion 43, and thus is capable of ensuring the sliding performance and the sealing performance. [0041]
Further, an excess of the refrigerating machine oil supplied from the oil feed holes 47, 48, and 50 but not retained as the oil film at the sliding parts passes through the gap between the crankshaft 4 and the upper shaft bearing 33 and the gap between the crankshaft 4 and the lower shaft bearing 34 and is discharged into the sealed container 1, or enters the operation chamber and is discharged into the sealed container 1 from the discharge port. The refrigerating machine oil discharged into the sealed container 1 returns to the bottom portion of the sealed container 1, and is again suctioned up into the oil feed passage 45. [0042]
Meanwhile, to manufacture a small, high-output air-conditioning apparatus, the hermetic compressor also needs to achieve a compression mechanism unit having a small exterior and a large excluded volume. Further, a refrigerant proposed for use for global environmental protection and used under a low compression condition does not have the same potential as that of an existing refrigerant unless the circulation amount of the refrigerant through the refrigerant circuit is increased. It is therefore necessary to realize a compression mechanism unit having a large excluded volume. [0043]
As a method of increasing the excluded volume, there is a method of providing a plurality of cylinders in the compression mechanism unit. Providing a plurality of cylinders, however, results in the extension of the compressor in the axial direction, that is, the height direction, and thus is insufficient to reduce the size of the exterior. Further, providing a plurality of cylinders complicates the compression mechanism unit, and increases the number of components and a design load for ensuring the reliability, resulting in a substantial increase in cost. [0044]

To increase the excluded volume while maintaining or reducing the size of the current compressor, it is optimal to increase the eccentricity amount of the eccentric shaft portion of the crankshaft while maintaining the inner diameter of the cylinder chamber of the compression mechanism unit. [0045]
However, if the eccentricity amount of the eccentric shaft portion 43 is increased in a configuration in which a reference line M of an outer circumferential surface in the counter-eccentric direction included in the outer circumferential surface in the radial direction of the eccentric shaft portion 43, a reference line L of an outer circumferential surface on the side of the counter-eccentric direction of the eccentric shaft portion 43 included in the outer circumferential surface in the radial direction of the main shaft portion 41, and a reference line N of an outer circumferential surface on the side of the counter-eccentric direction of the eccentric shaft portion 43 included in the outer circumferential surface in the radial direction of the sub-shaft portion 42 are aligned on a straight line, as in the view of the crankshaft 4 in Fig. 9, it is necessary to increase the diameter of the eccentric shaft portion 43 and reduce the outer diameter of the rolling piston 32, as in Fig. 10. That is, the thickness in the radial direction of the rolling piston 32 is reduced.
Fig. 10 is a diagram illustrating a state in which the eccentricity amount of the eccentric shaft portion 43 is increased, with (a) illustrating a case of a small eccentricity amount before the increase in the eccentricity amount, and (b) illustrating a case of a large eccentricity amount after the increase in the eccentricity amount of the eccentric shaft portion 43 in a configuration in which the reference lines L, M, and N of the crankshaft 4 are aligned on a straight line, with no change in the size of the cylinder chamber 36 in (a), that is, with no change in the position of the inner circumferential surface in the radial direction of the cylinder 31.
The reference lines L, M, and N are lines obtained by connecting points of intersection of straight lines each connecting the center of the eccentric shaft portion 43 and the center of the main shaft portion 41 and the sub-shaft portion 42 and the

respective outer circumferentia! surfaces in the counter-eccentric direction of the main shaft portion 41, the sub-shaft portion 42, and the eccentric shaft portion 43.
In the above configuration, the reference line M of the eccentric shaft portion 43 and the respective reference lines L and N of the main shaft portion 41 and the sub-shaft portion 42 are aligned on a straight line. A configuration having the reference lines L, M, and N not aligned on a straight line, on the other hand, does not allow the cylindrical rolling piston 32 inserted from the side of the main shaft portion 41 or the sub-shaft portion 42 to be inserted up to the eccentric shaft portion 43, preventing the rolling piston 32 from being assembled to the eccentric shaft portion 43. To assemble the rolling piston 32 to the crankshaft 4, therefore, the respective shaft portions need to be configured such that the reference lines L, M, and N of the respective outer circumferential surfaces in the counter-eccentric direction of the shaft portions are aligned on a straight line. [0046]
In this case, the increase in the diameter of the eccentric shaft portion 43 increases the distance from the oil feed hole 47 or 48 to the outer circumferential surface in the radial direction and the eccentric direction of the eccentric shaft portion 43 or to the outer circumferential surface in the eccentric direction of the rolling piston 32. Thus, the force for transporting the refrigerating machine oii to these outer circumferential surfaces is reduced, making it difficult for the refrigerating machine oil to reach the outer circumferential surfaces from the oil feed holes 47 and 48. That is, the supply of the refrigerating machine oil is discontinued, and the refrigerating machine oil is insufficiently fed to the outer circumferential surfaces, resulting in the degraded lubrication performance and the accelerated abrasion of components or the damage to the sliding parts. [0047]
The reduction in the thickness in the radial direction of the roiling piston 32 reduces the area of the end surfaces in the axial direction of the rolling piston 32, resulting in a reduction in the retention amount of the refrigerating machine oil retained between the end surface in the axial direction of the rolling piston 32 on the

side of the upper shaft bearing 33 and the flat surface of the upper shaft bearing 33 on the side of the rolling piston 32 or between the end surface in the axial direction of the rolling piston 32 on the side of the lower shaft bearing 34 and the flat surface of the lower shaft bearing 34 on the side of the rolling piston 32, eventually causing oil shortage. In particular, portions of the end surfaces in the axial direction of the rolling piston 32 in the eccentric direction of the eccentric shaft portion 43 are distant from the openings of the oil feed holes 47, 48, and 50. At these portions of the end surfaces, therefore, the supply of the refrigerating machine oil is discontinued, resulting in the exhaustion of the refrigerating machine oil and the accelerated abrasion of the sliding parts or the damage to the sliding parts. [0048]
To prevent the oil shortage, another method is conceivable which increases the diameter of each of the oil feed holes or increases the number of oil feed holes to increase the amount of the refrigerating machine oil to be supplied. This method, however, also increases the excess oil failing to be retained at the sliding parts. Although the excess oil is discharged into the sealed container 1, some of the excess oil does not directly return to the bottom portion of the sealed container 1, but returns to the sealed container 1 by routing through the discharge pipe 11 and the external circuit connected to the hermetic compressor 100, that is, the condenser 102, the expansion valve 103, the evaporator 104, and the suction muffler 101. Meanwhile, the refrigerating machine oil is not for exchanging heat in the condenser 102 and the evaporator 104 to perform evaporation and condensation. Therefore, the increase of the refrigerating machine oil circulating through the external circuit does not contribute to the transmission of the heat energy of the heat pump apparatus, and only reduces the circulation amount of the refrigerant. The increase of the refrigerating machine oil circulating through the external circuit, therefore, hinders the heat exchange of the refrigerant in the evaporator 104 and the condenser 102, and reduces the efficiency of the refrigeration cycle, degrading the performance of the entire heat pump apparatus. Further, if the refrigerating machine oil in the sealed container 1 is excessively drawn to the outside of the sealed container 1, the refrigerating machine

oil to be supplied to the sliding parts is exhausted, resulting in the damage to the sliding parts. Accordingly, the increase of the excess oil is undesirable. [0049]
Further, if an oil feed hole is provided in the eccentric direction of the eccentric shaft portion 43, as illustrated in Figs. 11 and 12, the repulsive force of the refrigerant gas applied to the rolling piston 32 during the compression of the refrigerant gas in the cylinder chamber by the rolling piston 32 is transmitted to the oil film formed on the rolling piston 32 and the eccentric shaft portion 43 and the refrigerating machine oil in the oil feed hole in the eccentric direction of the eccentric shaft portion 43. The repulsive force acts as force directed toward the oil feed passage 45 from the outer circumferential surface in the eccentric direction of the eccentric shaft portion 43 along the oil feed hole provided in the eccentric direction of the eccentric shaft portion 43. Thus, a situation arises in which the refrigerating machine oil fails to be discharged from the oil feed hole provided in the eccentric direction, or is pushed back into the oil feed passage 45.
Fig. 11 is a view of the crankshaft 4 as viewed from the side of the sub-shaft, and Fig. 12 is a view of the crankshaft 4 as viewed in the radial direction.
In the oil feed hole provided in the eccentric direction of the eccentric shaft portion 43, the refrigerating machine oil is transported through the oil feed hole from the oil feed passage 45 to the outer circumferential surface in the eccentric direction of the eccentric shaft portion 43 by centrifugal force (Fa) due to the rotation of the crankshaft 4, and is discharged to the outer circumferential surface. Meanwhile, when the rolling piston 32 compresses the refrigerant gas suctioned into the cylinder chamber, that is, the operation chamber, repulsive force (Fb), with which the compressed refrigerant gas expands to return to the previous state, is applied to the rolling piston 32. The repulsive force of the refrigerant applied to the rolling piston 32 is applied, via the rolling piston 32, to the oil film between the rolling piston 32 and the eccentric shaft portion 43 and the outer circumferential surface in the eccentric direction of the eccentric shaft portion 43. The force applied to the oil film, that is, the refrigerating machine oil, is directly transmitted to the refrigerating machine oil in

the oil feed hole, and acts as force directed toward the oil feed passage 45 from the outer circumferential surface in the eccentric direction of the eccentric shaft portion 43 along the oil feed hole, that is, force acting in the opposite direction to the direction of the centrifugal force of the crankshaft 4. The force prevents the discharge of the refrigerating machine oil to the outer circumferential surface in the eccentric direction of the eccentric shaft portion 43, or pushes the refrigerating machine oil back into the oil feed passage 45.
These phenomena are prominent particularly when the oil feed passage is long. The refrigerating machine oil in the oil feed hole provided in the eccentric direction stagnates or reciprocates between an opening of the oil feed hole and the oil feed passage 45, leading to a phenomenon in which the refrigerating machine oil is not discharged from the opening. Further, these phenomena are more prominent when the repulsive force of the refrigerant gas is increased by a factor such as an increase in the excluded volume or an increase in the rotation speed of the compression mechanism unit. Accordingly, the oil fails to be fed from the oil feed hole in the eccentric direction, resulting in the exhaustion of the refrigerating machine oil and the damage to the sliding parts. [0050]
Further, if the oil feed hole provided in the eccentric direction is on the same plane as that of the oil feed hole 50 in a plane perpendicular to the axial direction of the crankshaft 4 and is provided to face the oil feed hole 50 across the oil feed passage 45 in the radial direction of the crankshaft 4, the diameter of the oil feed hole in the eccentric direction is the same as or greater than the diameter of the oil feed hole 50, and a cross section of the oil feed hole in the eccentric direction taken along a plane perpendicular to the radial direction of the crankshaft 4 is the same as or larger than a cross section of the oil feed hole 50 taken along a plane perpendicular to the radial direction of the crankshaft 4, large centrifugal force is applied to the oil feed hole in the eccentric direction. Therefore, a large amount of the refrigerating machine oil is suctioned from the oil feed passage 45 under a condition in which the compressed refrigerant gas has low repulsive force and no large force is transmitted

to the oil film between the rolling piston 32 and the eccentric shaft portion 43 or to the refrigerating machine oi! in the oil feed hole in the eccentric direction of the eccentric shaft portion 43. Therefore, the refrigerating machine oil in the oil feed passage 45 is exhausted, and the oil feed hole 50 having low centrifugal force fails to suction the refrigerating machine oil from the oil feed passage 45. Thereby, the supply of the refrigerating machine oil from the oil feed hole 50 is reduced or discontinued, making the refrigerating machine oil at the sliding parts more likely to be exhausted.
Under a condition in which the compressed refrigerant gas has large repulsive force and large force is transmitted to the oil film between the rolling piston 32 and the eccentric shaft portion 43 and the refrigerating machine oil in the oil feed hole in the eccentric direction of the eccentric shaft portion 43, on the other hand, the oil feed hole 50 draws the refrigerating machine oil in the oil feed hole in the eccentric direction faced by the oil feed hole 50 across the oil feed passage 45, and hinders the discharge of the refrigerating machine oil. Therefore, the oil feeding is more likely to be discontinued, and the oil is more likely to be exhausted. [0051]
In the hermetic compressor 100, therefore, the eccentric shaft portion 43 has oil feed passages and oil feed holes in the radial direction and the eccentric direction and oil feed passages and an oil feed hole in the axial direction, as in Figs. 13, 14, 15, and 16, to allow the refrigerating machine oil to be supplied to the outer circumferential surface in the radial direction and the eccentric direction of the eccentric shaft portion 43 and the outer circumferential surface in the eccentric direction of the rolling piston 32. Fig. 13 is an enlarged view of the exterior of the crankshaft 4, and Fig. 14 is a view of the crankshaft 4 in Fig. 12, as viewed from the side of the sub-shaft portion 42. Fig. 15 is a sectional view for supplementing Fig. 13, illustrating the crankshaft 4 cut along Z-Z' in Fig. 14 corresponding to a plane perpendicular to the radial direction. Fig. 16 is a diagram supplementing these diagrams. [0052]

Specifically, the eccentric shaft portion 43 has, as first oil feed holes, an oil feed hole 53 and an oil feed hole 54 each communicating with the oil feed passage 45 and opening to the outer circumferential surface in the radial direction and the eccentric direction of the eccentric shaft portion 43, and also has, as a second oil feed hoie, an oil feed hole 55 in the axial direction communicating with the oil feed holes 53 and 54. Further, the oil feed hole 55 as the second oil feed hoie opens to first gaps 65 and 66 (illustrated in Fig. 16), which are formed between the flat surface of the lower shaft bearing 34 on the side of the eccentric shaft portion 43 and the outer circumferential surface E as a non-sliding surface of the eccentric shaft portion 43 and between the flat surface of the upper shaft bearing 33 on the side of the eccentric shaft portion 43 and the outer circumferential surface G as a non-sliding surface of the eccentric shaft portion 43, respectively. The oil feed holes 53 and 54 as the first oil feed holes open to second gaps 67 and 68 (illustrated in Fig. 16), respectively, which are formed between the inner circumferential surface of the rolling piston 32 corresponding to the inner diameter thereof and the outer circumferential surface B as a non-sliding surface of the eccentric shaft portion 43 and between the inner circumferential surface of the rolling piston 32 corresponding to the inner diameter thereof and the outer circumferential surface C as a non-sliding surface of the eccentric shaft portion 43, respectively. [0053]
The oil feed hole 53 is formed of an opening 56 which opens to the outer circumferential surface B in the eccentric direction of the eccentric shaft portion 43 included in the outer circumferential surface in the radial direction of the eccentric shaft portion 43, and which is a non-projecting portion, that is, a non-sliding surface, and an oil feed passage 60 that allows communication between the oil feed passage 45 and the opening 56. On a plane perpendicular to the axial direction of the crankshaft 4, the oil feed passage 60 is provided not to be on the same plane as that of the oil feed hole 50 provided as a third oil feed hole. For example, in the axial direction of the crankshaft 4, the oil feed hole 53 is caused to communicate with the oil feed passage 45 between the position at which the oil feed hole 47 communicates

with the oil feed passage 45 and the position at which the oil feed hole 50 communicates with the oi! feed passage 45. Thereby, the oil feed hole 53 and the oil feed hole 50 do not face each other across the oil feed passage 45. The oil feed hole 47 is provided in the sub-shaft portion 42. In the axial direction of the crankshaft 4, therefore, if the oil feed hole 53 is caused to communicate with the oil feed passage 45 between the outer circumferential surface in the axial direction of the eccentric shaft portion 43 on the side of the sub-shaft portion 42 and the position at which the oil feed hole 50 communicates with the oil feed passage 45, a similar effect is obtained. In the radial direction of the crankshaft 4, on the other hand, the oil feed hole 53 and the oil feed hole 50 may face each other across the oil feed passage 45.
Further, the oil feed hole 53 is configured to open to the second gap 67 formed by the inner circumferential surface of the rolling piston 32 corresponding to the inner diameter thereof and the outer circumferential surface B of the eccentric shaft portion 43, and thus is capable of discharging the refrigerating machine oil into the gap 67.
The refrigerating machine oil is transported from the oil feed passage 45 to the opening 56 by the centrifugal force due to the rotation of the crankshaft 4. [0054]
Similarly, the oil feed hole 54 is formed of an opening 57 which opens to the outer circumferential surface C in the eccentric direction of the eccentric shaft portion 43 included in the outer circumferential surface in the radial direction of the eccentric shaft portion 43, and which is a non-projecting portion, that is, a non-sliding surface, and an oil feed passage 61 that allows communication between the oil feed passage 45 and the opening 57. On a plane perpendicular to the axial direction of the crankshaft 4, the oil feed passage 61 is provided not to be on the same plane as that of the oil feed hole 50 provided as the third oil feed hole. For example, in the axial direction of the crankshaft 4, the oil feed passage 61 is caused to communicate with the oil feed passage 45 between the position at which the oil feed hole 48 communicates with the oil feed passage 45 and the position at which the oil feed hole 50 communicates with the oil feed passage 45. Thereby, the oil feed hole 54 and the oil feed hole 50 do not face each other across the oil feed passage 45. The oil

feed hole 48 is provided in the main shaft portion 41. In the axial direction of the crankshaft 4, therefore, if the oil feed hole 54 is caused to communicate with the oil feed passage 45 between the outer circumferential surface in the axial direction of the eccentric shaft portion 43 on the side of the main shaft portion 41 and the position at which the oil feed hole 50 communicates with the oil feed passage 45, a similar result is obtained. In the radial direction of the crankshaft 4, on the other hand, the oil feed hole 54 and the oil feed hole 50 may face each other across the oil feed passage 45.
Further, the oil feed hole 54 is configured to open to the second gap 68 formed by the inner circumferential surface of the roiling piston 32 corresponding to the inner diameter thereof and the outer circumferential surface C of the eccentric shaft portion 43, and thus is capable of discharging the refrigerating machine oii into the gap 68.
The refrigerating machine oil is transported from the oil feed passage 45 to the opening 57 by the centrifugal force due to the rotation of the crankshaft 4. [0055]
Further, the oil feed holes 53 and 54 are set such that the sum of the respective cross sections thereof in a direction perpendicular to the flow direction of the refrigerating machine oil flowing through the oil feed holes 53 and 54 is less than the cross section of the oil feed hole 50 in a direction perpendicular to the flow direction of the refrigerating machine oil flowing through the oil feed hole 50. Specifically, The oil feed holes 53 and 54 are set such that (a + b) < c holds where "a" represents a cross-sectional area at a cross-section of the oil feed hole 53 taken along a plane perpendicular to the flow direction of the refrigerating machine oil flowing through the oil feed passage 60, that is, the radial direction of the crankshaft 4, "b" represents a cross-sectional area at a cross-section of the oil feed hole 54 taken along a plane perpendicular to the flow direction of the refrigerating machine oil flowing through the oil feed passage 61, that is, the radial direction of the crankshaft 4, and "c" represents a cross-sectional area at a cross-section of the oil feed hole 50 taken along a plane perpendicular to the flow direction of the refrigerating machine oil flowing through the oil feed passage 52, that is, the radial direction of the crankshaft 4. . Further, it is desirable that the ratio of the cross sections a and b to the cross section c

corresponds to the ratio (inversely proportional) of the sum of a size x of the oil feed passage 60 of the oil feed hole 53 and a size y of the oil feed passage 61 of the oil feed hole 54 to a size z of the oil feed passage 52 of the oil feed hole 50. [0056]
The oil feed hole 55 is formed of an opening 58 that opens to the outer circumferential surface E as a non-sliding surface in the axial direction of the eccentric shaft, an opening 59 that opens to the outer circumferential surface G as a non-sliding surface in the axial direction of the eccentric shaft, an oil feed passage 62 communicating between the opening 58 and the oil feed passage 60, an oil feed passage 63 communicating between the opening 59 and the oil feed passage 61, and an oil feed passage 64 communicating between the oil feed passages 60 and 61. The oil feed passages 62, 63, and 64 are provided to pass through from the opening 58 in the outer circumferential surface E to the opening 59 in the outer circumferential surface G.
Thereby, the opening 58 is configured to open to the first gap 65 formed between the flat surface of the lower shaft bearing 34 on the side of the eccentric shaft portion 43 and the outer circumferential surface E of the eccentric shaft portion 43, and thus is capable of discharging the refrigerating machine oil into the gap 65. The opening 59 is configured to open to the first gap 66 formed between the flat surface of the upper shaft bearing 33 on the side of the eccentric shaft portion 43 and the outer circumferential surface G of the eccentric shaft portion 43, and is capable of discharging the refrigerating machine oil into the gap 66. [0057]
Further, the oil feed hole 55 is set such that the sum of the respective cross-sectional areas of the cross-sections of the oil feed holes 53 and 54 in the direction perpendicular to the flow direction of the refrigerating machine oil flowing through the oil feed holes 53 and 54 is equal to or less than the cross-sectional area of the oil feed hole 55 in the direction perpendicular to the flow direction of the refrigerating machine oil flowing through the oil feed hole 55. Specifically, the cross-sectional areas at cross-sections a and b of the oil feed holes 53 and 54 are represented as (a

+ b) < d where "d" represents a cross-sectional area of the oil feed hole 55 taken along a plane perpendicular to the flow direction of the refrigerating machine oil flowing through the oil feed passages 62, 63, and 64, that is, the axial direction of the crankshaft 4, Further, it is desirable that the ratio of the cross sections a and b to the cross section d corresponds to the ratio (inversely proportional) of the sum of the size x of the oil feed passage 60 of the oil feed hole 53 and the size y of the oil feed passage 61 of the oil feed hole 54 to a size w of the oil feed passages 62, 63, and 64 of the oil feed hole 55.
There is no setting for the relationship between the oil feed hole 50 and the oil feed hole 55. For example, the oil feed hole 50 and the oil feed hole 55 may have the same diameter. [0058]
As described above, in a plane perpendicular to the axial direction of the crankshaft 4, each of the oil feed holes 53 and 54 is provided not to be on the same plane as that of the oil feed hole 50, and is configured such that the sum of the cross section a of the oil feed passage 60 of the oil feed hole 53 and the cross section b of the oil feed passage 61 of the oil feed hole 54 is less than the cross section c of the oil feed passage 52 of the oil feed hole 50. Even if the centrifugal force in the eccentric direction is applied to the oil feed holes 53 and 54, therefore, there is no suction of a large amount of the refrigerating machine oil from the oil feed passage 45, preventing the oil'feed hole 50 from failing to suction the refrigerating machine oil from the oil feed passage 45. That is, the suction of the refrigerating machine oil by the oil feed hole 50 is not hindered. [0059]
Meanwhile, the oil feed hole 55 opens in the axial direction, and thus is not subjected to the centrifugal force, and has low power to transport the refrigerating machine oil. With the increase of the cross section d of the oil feed hole 55, however, the pressure loss is reduced, and the transport power is ensured. Even if the transport power of the oil feed hole 55 to transport the refrigerating machine oil is

lower than that of the oil feed holes 50, 53, and 54, the oil feed hole 55 is capable of
supplying a sufficient amount of refrigerating machine oil.
[0060]
Further, the oil feed hole 53 and the oil feed hole 54 open to the outer circumferential surface B and the outer circumferential surface C, respectively, and thus communicate with the space formed by the outer circumferential surface B of the eccentric shaft portion 43 and the inner circumferential surface of the rolling piston 32 corresponding to the inner diameter thereof and the space formed by the outer circumferential surface C of the eccentric shaft portion 43 and the inner circumferential surface of the rolling piston 32 corresponding to the inner diameter thereof, respectively. Therefore, even if the repulsive force of the compressed refrigerant gas, which is applied to the rolling piston 32 when the refrigerant gas in the cylinder chamber starts to be compressed, is transmitted to the oil film formed on the rolling piston 32 and the eccentric shaft portion 43 and the refrigerating machine oil in the oil feed passages 60 and 61 of the oil feed holes 53 and 54, the refrigerating machine oil stored in the space formed by the outer circumferential surface B of the eccentric shaft portion 43 and the inner circumferential surface of the rolling piston 32 corresponding to the inner diameter thereof and the space formed by the outer circumferential surface C of the eccentric shaft portion 43 and the inner circumferential surface of the rolling piston 32 corresponding to the inner diameter thereof, that is, the second gaps 67 and 68, acts as a buffer, mitigating the transmission of the repulsive force of the compressed refrigerant gas. Therefore, the push-back of the refrigerating machine oil toward the oil feed passage 45 is suppressed. [0061]
Even if the repulsive force of the compressed refrigerant gas applied to the outer circumferential surface of the eccentric shaft portion 43 is large, and the refrigerating machine oil in the oil feed passages 60 and 61 of the oil feed holes 53 and 54 is pushed back toward the oil feed passage 45, the pushed-back refrigerating machine oil (Vd) collides with the refrigerating machine oil (Va) transported from the

oil feed passage 45 to the openings 56 and 57 by the centrifugal force, and flows into the oil feed hole 55, as in Fig. 16. The refrigerating machine oil (Ve) flowing into the oil feed hole 55 is discharged from the opening 58 into the space formed by the outer circumferential surface E of the eccentric shaft portion 43 and the flat surface of the lower shaft bearing 34 on the side of the eccentric shaft portion 43, that is, the first gap 65, and is discharged from the opening 59 into the space formed by the outer circumferential surface G of the eccentric shaft portion 43 and the flat surface of the lower shaft bearing 34 on the side of the eccentric shaft portion 43, that is, the first gap 66. The first gap 65 communicates with the space formed by the outer circumferential surface B of the eccentric shaft portion 43 and the inner circumferential surface of the rolling piston 32 corresponding to the inner diameter thereof, that is, the second gap 67, and the first gap 66 communicates with the space formed by the outer circumferential surface C of the eccentric shaft portion 43 and the inner circumferential surface of the rolling piston 32 corresponding to the inner diameter thereof, that is, the second gap 68. The first gap 65 and the second gap 67 also communicate with the space between the rolling piston 32 and the lower shaft bearing 34, that is, a gap 69, and the first gap 66 and the second gap 68 also communicate with the space between the rolling piston 32 and the upper shaft bearing 33, that is, a gap 70. Therefore, the refrigerating machine oil discharged from the oil feed hole 55 also flows into between the eccentric shaft portion 43 and the rolling piston 32, between the rolling piston 32 and the upper shaft bearing 33, and between the rolling piston 32 and the lower shaft bearing 34. It is thereby possible to suppress the exhaustion of the refrigerating machine oil between the eccentric shaft portion 43 and the rolling piston 32, between the rolling piston 32 and the upper shaft bearing 33, and between the rolling piston 32 and the lower shaft bearing 34. This effect is enhanced particularly when the repulsive force of the compressed refrigerant gas is increased by the increase in the excluded volume or the increase in the rotation speed of the compression mechanism unit. [0062]

Further, in a plane perpendicular to the axial direction of the crankshaft 4, each of the oil feed holes 53 and 54 is provided not to be on the same plane as that of the oil feed hole 50. It is therefore possible to discharge the refrigerating machine oil from the oil feed holes 53 and 54 and the oil feed hole 50, irrespective of the level of the repulsive force of the compressed refrigerant gas.
Further, even if the refrigerating machine oil in the oil feed holes 53 and 54 stagnates or reciprocates in the oil feed passages 60 and 61, the refrigerating machine oil in the oil feed passages 60 and 61 flows into the oil feed hole 55 and is discharged from the openings 58 and 59. it is therefore possible to supply the refrigerating machine oil without stagnation of the refrigerating machine oil in the oil feed passages 60 and 61. [0063]
Further, the cross section d of the oil feed hole 55 is equal to or greater than the sum of the respective cross sections a and b of the oil feed holes 53 and 54. Even if the repulsive force of the compressed refrigerant gas makes it difficult to transport the refrigerating machine oil in the oil feed holes 53 and 54 to the openings 56 and 57 from the oil feed passage 45, therefore, the resistance such as the pressure loss is low in the oil feed hole 55, and thus the refrigerating machine oil is likely to flow into and be discharged from the oil feed hole 55. That is, if the refrigerating machine oil fails to be discharged from the oil feed holes 53 and 54, the refrigerating machine oil is actively discharged from the oil feed hole 55, and thus is capable of compensating for insufficient supply of the refrigerating machine oil. [0064]
Even if the diameter of the eccentric shaft portion 43 of the crankshaft 4 is increased, therefore, it is possible to continuously supply the refrigerating machine oil from the oil feed passage 45 of the crankshaft 4 to the outer circumferential surface in the eccentric direction of the eccentric shaft portion 43 and the outer circumferential surface in the eccentric direction of the rolling piston 32 via the oil feed holes 53, 54, and 55. It is thus possible to form an oil film between the outer circumferential surface in the eccentric direction of the eccentric shaft portion 43 and the inner

circumferential surface of the rolling piston 32 corresponding to the inner diameter thereof, between an outer circumferential surface in the axial direction and the eccentric direction of the eccentric shaft portion 43 and the outer circumferential surface of the upper shaft bearing 33 on the side of the eccentric shaft portion 43, between an outer circumferential surface in the axial direction and the eccentric direction of the eccentric shaft portion 43 and the outer circumferential surface of the lower shaft bearing 34 on the side of the eccentric shaft portion 43, between an outer circumferential surface in the axial direction of the rolling piston 32 and the outer circumferential surface of the upper shaft bearing 33 on the side of the rolling piston 32, and between an outer circumferential surface in the axial direction of the rolling piston 32 and the outer circumferential surface of the lower shaft bearing 34 on the side of the rolling piston 32. [0065]
Further, the refrigerant and the refrigerating machine oil have a characteristic that the refrigerant dissolves into the refrigerating machine oil when the refrigerant and the refrigerating machine oil are left at low temperature for an extended period of time. If the compressor is operated in this state, the temperature inside the sealed container rises, and the refrigerant in the refrigerating machine oil suddenly evaporates and foams. If the foaming phenomenon occurs in each of the oil feed passages, the refrigerating machine oil may stagnate in the oil feed passages and cause the discontinuation of oil feeding. The discontinuation of oil feeding is likely to occur particularly when the foaming phenomenon occurs in an oil feed hole in the eccentric direction having a long oil feed passage with a small diameter. However, the oil feed hole 50 is provided in the counter-eccentric direction, and the oil feed holes 53 and 54 are provided in the eccentric direction. Even if the oil feeding is discontinued in one of the oil feed holes owing to the foaming phenomenon, therefore, it is possible to supply the refrigerating machine oil to the outer circumferential surface in the eccentric direction of the eccentric shaft portion 43 and the outer circumferential surface in the eccentric direction of the rolling piston 32 through the rest of the oil feed holes.

[0066]
Further, the oil feed hole 55 in the axial direction is provided to allow the communication between the plurality of oil feed holes 53 and 54 in the eccentric direction. Even if the foaming phenomenon occurs in one of the oil feed passages of the oil feed holes 53 and 54, therefore, the refrigerating machine oil flows into the oil feed hole 55 from the remaining oil feed passage, making a prompt recovery from the state in which the oil feed passage has run out of the refrigerating machine oil. It is thus possible to suppress the discontinuation of the supply of the refrigerating machine oil to the outer circumferential surface in the eccentric direction of the eccentric shaft portion 43 and the outer circumferential surface in the eccentric direction of the rolling piston 32. [0067]
The above-described configuration is capable of feeding the oil without discontinuation of oil feeding to the outer circumferential surface in the eccentric direction of the eccentric shaft portion and the outer circumferential surface in the eccentric direction of the rolling piston, even if the excluded volume is increased by the increase in the eccentricity amount of the eccentric shaft portion of the crankshaft while the height and the inner diameter of the cylinder are maintained. It is therefore possible to ensure the lubrication performance of lubricating the sliding parts of the compression mechanism unit to suppress the abrasion of the moving parts, and maintain the sealing performance of sealing the compression mechanism unit to reduce the leakage loss of the compression chamber. Accordingly, it is possible to obtain a high-performance, reliable hermetic compressor. [0068]
The description has been given of a single-cylinder hermetic compressor, in which the compression mechanism unit includes a single cylinder, a single roiling piston, and a single eccentric shaft portion of the crankshaft. However, the present invention may be implemented with a hermetic compressor including a plurality of cylinders. For example, even if the present invention is implemented with a double-cylinder hermetic compressor, similar operations and effects are obtained.

Further, the description has been given of a configuration in which the roiling piston and the vane are separated from each other. However, the effects of the configuration are unchanged, even if the rolling piston and the vane are integrated together. Similar operations and effects are obtained. [0069]
Further, the description has been given of an example having two oil feed holes provided in the eccentric shaft direction, which are the oil feed holes 53 and 54. However, the number of oil feed holes in the eccentric shaft direction is not limited. Further, similar effects are obtainable even with a single oil feed hole in the eccentric shaft direction.
Further, the oil feed hole in the axial direction is not limited to the oil feed hole 55, and a plurality of oil feed holes in the axial direction may be provided. Similar effects are obtainable even with a plurality of oil feed holes in the axial direction. [0070]
Further, each of the oil feed passages 60 and 61 of the oil feed holes 53 and 54 does not need to have the same diameter from a leading end to a trailing end thereof. In that case, each of the cross sections a and b is regarded as the mean cross section of cross sections from the leading end to the trailing end.
Further, each of the oil feed passages 62, 63, and 64 of the oil feed hole 55 does not need to have the same diameter from a leading end to a trailing end thereof. The oil feed passages 62, 63, and 64 may have different diameters. Reference Signs List [0071]
1 sealed container 2 electric motor mechanism unit 3 compression mechanism unit 4 crankshaft 11 discharge pipe 12 suction connection pipe 21 stator 22 rotator 23 terminal 31 cylinder 32 roiling piston 33 upper shaft bearing 34 lower shaft bearing 35 vane 36 cylinder chamber 37 vane groove 38 back pressure chamber 41 main shaft portion 42 sub-shaft portion 43 eccentric shaft portion 44 projecting portion 45 oil feed passage 46 opening 47, 48 oil feed hole 49 cutout 50 oil feed hole 51

opening 52 oil feed passage 53, 54, 55 oil feed hole 56, 57, 58, 59 opening 60, 61, 62, 63, 64 oil feed passage 65, 66 first gap 67, 68 second gap 69, 70 gap between piston and shaft bearing 100 hermetic compressor 101 suction muffler 102 condenser 103 expansion valve 104 evaporator

CLAIMS
[Claim 1]
A hermetic compressor including a sealed container storing refrigerating machine oil, the sealed container housing a compression mechanism unit, the compression mechanism unit comprising:
a crankshaft having an oil feed passage through which the refrigerating machine oil is suctioned up and an eccentric shaft portion;
a cylinder housing the eccentric shaft portion and having a cylinder chamber;
shaft bearings that close the cylinder chamber and support the crankshaft; and
a cylindrical piston attached to the eccentric shaft portion, and the eccentric shaft portion having
a first oil feed hole communicating with the oil feed passage of the crankshaft, and having an opening in an outer circumferential surface in an eccentric direction of the eccentric shaft portion, and
a second oil feed hole communicating with the first oil feed hole, and having an opening in an outer circumferential surface in an axial direction of the eccentric shaft portion. [Claim 2]
The hermetic compressor of claim 1, wherein the compression mechanism unit has a first gap between an outer circumferential surface of one of the shaft bearings on a side of the cylinder and the outer circumferential surface in the axial direction of the eccentric shaft portion, and
wherein the second oil feed hole opens to the first gap. [Claim 3]
The hermetic compressor of claim 1 or 2, wherein the compression mechanism unit has the second gap between an inner circumferential surface of the piston and an outer circumferential surface in a radial direction of the eccentric shaft portion, and wherein the first oil feed hole opens to the second gap.

[Claim 4]
The hermetic compressor of any one of claims 1 to 3, wherein the eccentric shaft portion has a third oil feed hole having an opening in an outer circumferential surface on a side opposite to the eccentric direction of the eccentric shaft portion, and
wherein the first oil feed hole is provided between the outer circumferential surface in the axial direction of the eccentric shaft portion and the third oil feed hole. [Claim 5]
The hermetic compressor of any one of claims 1 to 4, wherein a plurality of the first oil feed holes are provided in a radial direction. [Claim 6]
The hermetic compressor of claim 5, wherein the plurality of first oil feed holes communicate with each other through the second oil feed hole. [Claim 7]
The hermetic compressor of any one of claims 4 to 6, wherein a cross-sectional area of the first oil feed hole at a cross-section in a direction perpendicular to a radial direction of the eccentric shaft portion is smaller than a cross-sectional area of the third oil feed hole at a cross-section in the direction perpendicular to the radial direction of the eccentric shaft portion.
[Claim 8]
The hermetic compressor of any one of claims 1 to 7, wherein a cross-sectional area of the first oil feed hole at a cross-section in a direction perpendicular to a radial direction of the eccentric shaft portion is equal to or smaller than a cross-sectional area of the second oil feed hole at a cross-section in a direction perpendicular to the axial direction of the eccentric shaft portion.