US20070020126A1

US20070020126A1 - Hermetic compressor

Info

Publication number: US20070020126A1
Application number: US11/435,686
Authority: US
Inventors: Kyu Shin
Original assignee: Samsung Gwangju Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2005-07-19
Filing date: 2006-05-18
Publication date: 2007-01-25
Also published as: KR100708551B1; JP2007024036A; CN1900519A; KR20070010520A; BRPI0601944A

Abstract

A hermetic compressor includes: a hermetic case; a frame configured to be received in the hermetic case, a drive unit and a compression unit arranged at lower and upper sides of the frame, respectively; a rotating shaft mounted to the frame and configured to transmit a rotational force of the drive unit to the compression unit and having an upper eccentric portion connected to the upper compression unit; and a connecting rod configured to be coupled to the eccentric portion. An oil bank may be formed at a surface of the eccentric portion of the rotating shaft that comes into contact with the connecting rod.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority under 35 U.S.C. § 119 to Korean Patent Application No. 2005-65184, filed Jul. 19, 2005, entire contents of which are incorporated herein by reference. This application may also be related to commonly owned U.S. patent application Ser. No. 11/199,170, filed Aug. 9, 2005, as well as commonly owned U.S. patent application Ser. No. 11/232,936, filed Sep. 23, 2005, the contents of each of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates to a hermetic compressor, and, more particularly, to a hermetic compressor having an improved oil supply structure capable of supplying a sufficient amount of oil into a space defined between an eccentric portion of a rotating shaft and a connecting rod.
2. Description of the Related Art
Japanese Patent Laid-Open Publication No. 63-85270 describes a conventional hermetic compressor in which oil is supplied into respective drive parts of the compressor by use of a rotational centrifugal force of a rotating shaft. According to the conventional structure for lubricating an eccentric portion of the rotating shaft, it is impossible to supply a sufficient amount of oil to the frictional region between the eccentric portion and a connection rod because an oil receiving gap between the connecting rod and the eccentric portion is extremely narrow. This results in insufficient lubrication, which causes excessive wear of the compressor components.
In particular, if a drive motor stops, the oil, which serves as a lubricant between the rotating shaft and the connecting rod, flows downward while only an extremely small amount of oil remains. As a result, the rotating shaft inevitably rotates with little or no oil lubrication until oil is again supplied when the compressor initially operates. As a result, wear of the compressor parts increases, as does the noise generated by the compressor.
Furthermore, since the eccentric portion of the rotating shaft exhibits poor lubrication when the maximum compression load is applied as the piston reaches a top dead point, durability and operational reliability of the rotating shaft are severely damaged.

SUMMARY OF THE INVENTION

The present invention has been made in order to solve the above problems. It is an aspect of the invention to provide a hermetic compressor capable of supplying a sufficient amount of oil into a frictional region between an eccentric portion of a rotating shaft and a connecting rod.
To this end, a first non-limiting aspect of the present invention provides a hermetic compressor, including: a hermetic case; a frame configured to be received in the hermetic case, a drive unit and a compression unit arranged at lower and upper sides of the frame, respectively; a rotating shaft mounted to the frame and configured to transmit a rotational force of the drive unit to the compressional unit and having an upper eccentric portion connected to the upper compression unit; and a connecting rod configured to be coupled to the eccentric portion, wherein an oil bank is formed at a surface of the eccentric portion of the rotating shaft that comes into contact with the connecting rod.
Another non-limiting aspect of the present invention provides a hermetic compressor, including: a case; a drive unit adapted to be received in the case; a compression until adapted to be received in the case; a rotating shaft configured to transmit a rotation a1 force of the drive unit to the compression unit, the rotating shaft including at least an eccentric portion; a connecting rod configured to be coupled to the eccentric portion and an oil bank positioned at a surface of the eccentric portion.
Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the exemplary embodiments of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, of which:
FIG. 1 is a sectional view showing a non-limiting example of an oil supply structure for an eccentric portion of a rotating shaft;
FIG. 2 is a sectional view showing a non-limiting example of an interior configuration of a hermetic compressor including an eccentric portion of a rotating shaft;
FIG. 3 is a sectional view showing an oil supply configuration including an oil bank formed at the eccentric portion of the rotating shaft according to a second non-limiting embodiment of the present invention;
FIGS. 4A to 4C are sectional views showing an oil supply configuration including an oil bank formed at the eccentric portion of the rotating shaft according to a third non-limiting embodiment of the present invention;
FIGS. 5A to 5C are sectional views showing an oil supply configuration including an oil bank formed at the eccentric portion of the rotating shaft according to a fourth non-limiting embodiment of the present invention;
FIG. 6 is a sectional view showing the a non-limiting example of the positional relationship between the rotating shaft, connecting rod, and piston when the piston reaches a top dead point;
FIGS. 7A to 7C are sectional views showing an oil supply configuration including an oil bank formed at the eccentric portion of the rotating shaft according to a fifth non-limiting embodiment of the present invention; and
FIGS. 8A to 8C are sectional views showing an oil supply configuration including an oil bank formed at the eccentric portion of the rotating shaft according to a sixth non-limiting embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The embodiments are described below to explain the present invention by referring to the figures.
Referring to FIG. 1, a rotating shaft of a hermetic compressor is illustrated in sectional view. As shown in FIG. 1, an oil pickup member (not shown) raises oil gathered in the bottom of a hermetic case when rotating shaft 10 rotates. To ensure smooth rising of the oil, the oil pickup member (not shown) may be connected to a lower end of the rotating shaft 10, and an eccentric channel (not shown) may be formed in the rotating shaft 10 at the top of the oil pickup member. The eccentric channel (not shown) may be eccentrically extended relative to the center of the rotating shaft. Also, a spiral channel 50, i.e., a spiral groove, may be formed at an outer circumferential surface of the rotating shaft to be connected to the eccentric channel.
The rotating shaft 10 may include an eccentric portion 20, which may have a hollow channel 30 centrally defined therein. To supply oil to a piston (not shown), a lower end of the hollow channel 30 may be connected to an upper end of the spiral groove 50 and an upper end of the hollow channel 30 may be open. A connection path 40 may be formed at a middle height of the hollow channel 30 to communicate with the hollow channel 30. Specifically, the connection path 40 may be extended in a radial direction of the eccentric portion 20 to supply oil to a contact region between the eccentric portion 20 and a connecting rod (not shown).
During operation of the hermetic compressor having the above-described configuration, if the rotating shaft rotates in a predetermined direction, oil is suctioned upward via the oil pickup member in accordance with rotation of the rotating shaft. Subsequently, the oil moves upward along the oil channel and the spiral groove of the rotating shaft due to the rotational centrifugal force of the rotating shaft. In this way, it is possible to transfer oil to respective frictional and high temperature regions.
A part of the rising oil is scattered upward via the hollow channel 30 formed in the eccentric portion 20, so that it is transferred to the frictional and high-temperature regions while flowing downward, thereby serving to lubricate and cool those regions. Also, a part of the oil transferred into the hollow channel 30 of the eccentric portion 20 is introduced into the connection path 40, thereby serving to lubricate and cool a frictional contact region between the eccentric portion 20 and the connecting rod.
The overall configuration of the hermetic compressor having an improved rotating shaft according to a non-limiting aspect of the present invention will be explained in detail with reference to FIG. 2. As shown in FIG. 2, the hermetic compressor may include: a frame 120 mounted in a hermetic case 100 by interposing a plurality of dampers 110; a compression unit 200 disposed on the top of the frame 120; and a drive unit 300 arranged beneath the frame 120 to drive the compression unit 200.
The hermetic compressor may further include a rotating shaft 400 for transmitting a rotational force of the drive unit 300 to the compression unit 200. The rotating shaft 400 may be vertically extended and may be rotatably supported by a shaft supporting portion of the frame 120. The rotating shaft 400 may include an eccentric portion 410 eccentrically formed at an upper end thereof relative to the center of the rotating shaft 400. The eccentric portion 410 may be used to connect the rotating shaft 400 to the compression unit 200. The rotating shaft 400 may also include a bearing supporting portion 420 formed at a lower end of the eccentric portion 410. The bearing supporting portion 420 of the rotating shaft 400 may have an outer diameter larger than the remaining portion of the rotating shaft 400 so that it can be supported on the top of the frame 120. A thrust bearing 430 may be interposed between a lower surface of the bearing supporting portion 420 and an upper surface of the frame 120 to support an axial load of the rotating shaft 400 while facilitating rotation of the rotating shaft 400.
The drive unit 300 may include a rotor 310 coupled to an outer surface of the rotating shaft 400 to rotate along with the rotating shaft 400, and a stator 320 affixed to an outer circumference of the rotor 310. The compression unit 200 may include a cylinder 210 and a cylinder head 220 which define a refrigerant compression chamber, a piston 230 arranged to reciprocate in the cylinder 210 to compress a refrigerant, and a connecting rod 250 having one end connected to a pin 240 of the piston 230 and the other end connected to the eccentric portion 410 of the rotating shaft 400. With this configuration, when the rotating shaft 400 rotates in accordance with operation of the drive unit 300, the eccentric portion 410 of the rotating shaft 400 and the connecting rod 250 convert rotating motion into linear reciprocating motion, so that the piston 230 is moved forward or backward to compress a refrigerant.
The hermetic compressor of the present invention having the above-described configuration may contain a predetermined amount of oil (L) in the bottom of the hermetic case 100 for the lubrication and cooling of respective drive parts. An oil pickup member 510 may be connected to a lower end of the rotating shaft 400 so that the oil (L) gathered in the bottom of the hermetic case 100 moves upward, thereby being transferred to the respective drive parts by use of a rotational centrifugal force of the rotating shaft 400. An eccentric hole 520 may be formed in the rotating shaft 400 above the oil pickup member 510 so that it may be spaced apart from the center of the rotating shaft 400 by a predetermined distance. The eccentric hole 520 may be used to move the oil (L) upward. Also, a spiral groove 530 may be formed at an outer circumferential surface of the rotating shaft 400 to communicate with the eccentric hole 520.
FIG. 3 is a sectional view showing an oil supply structure according to a second non-limiting embodiment of the present invention. As shown in FIG. 3, the spiral groove 530 may have a predetermined depth, and may be formed at an outer circumferential surface of the shaft 400. Thereby, oil can be guided upward along the spiral groove 530 when the rotating shaft 400 rotates. The upwardly moved oil serves to lubricate and cool both the outer surface of the rotating shaft 400 and the inner surface of the shaft supporting portion.
A communication bore 540 may be formed in a radial direction of the rotating shaft 400 at an upper location of the outer surface of the rotating shaft 400 so that the oil can be guided to the eccentric portion 410 after moving upward via the spiral groove 530. The eccentric portion 410 may be provided with a hollow channel 550. A lower end of the hollow channel 550 may be connected to the communication bore 540 and an upper end of the hollow channel 500 may be open, so that the oil can be supplied to the piston. A connection path 560 may be formed in a radial direction of the eccentric portion 410 at a middle height of the hollow channel 550 to communicate with the hollow channel 550, so that the oil can be supplied to a contact region between the eccentric portion 410 and the connecting rod (not shown).
An oil bank 600 may be formed around an outer circumferential surface of the eccentric portion 410 where the eccentric portion 410 comes into contact with the connecting rod. The oil bank 600 may be formed at the same location as the connection path 560, and may be formed as of a circumferential groove having a predetermined width and depth suitable to receive the oil discharged from the connection path 560.
Now, a process for supplying oil into the eccentric portion 410 of the rotating shaft 400 according to the above non-limiting embodiment of the present invention will be explained. First, if the compressor is driven, the oil gathered in the bottom of the compressor moves upward in a vortex flow form by successively passing through the oil pickup member, the eccentric hole, and the spiral groove due to the rotational centrifugal force of the rotating shaft. Then, the upwardly moved oil reaches the hollow channel of the eccentric portion by way of the communication bore, so that it is scattered upward via the hollow channel, thereby being transferred to frictional and high-temperature regions. A part of the rising oil is introduced into the connection path to reach the oil bank, thereby serving to lubricate and cool a frictional region between the eccentric portion and the connecting rod.
In particular, if the rotating shaft begins to rotate as the compressor initially operates, the remainder of the oil inside the oil bank is forced out of the oil bank by a centrifugal force. Thereby, the oil can serve to appropriately lubricate the eccentric portion of the rotating shaft even during a transition period until new oil is again supplied. This eliminates a risk of wear at the contact region between the eccentric portion and the connecting rod, achieving an improvement in the performance of the compressor.
Referring to FIGS. 4A to 4C, an oil supply structure according to a third non-limiting embodiment of the present invention is illustrated in sectional view. In the third non-limiting embodiment, an oil path may also be provided at an upper or lower location of the eccentric portion.
As shown in FIG. 4A, an upper linear groove 700, having a predetermined width and depth, may be formed at the outer circumferential surface of the eccentric portion 410 so that it extends from an upper end of the oil bank 600 to an upper end of the eccentric portion 410. With the use of the upper linear groove 700, after being supplied into the oil bank 600 through the connection path 560 of the eccentric portion 410, oil is able to move to the upper end of the eccentric portion 410 by a centrifugal force of the rotating shaft 400, thereby serving to lubricate a frictional region between the eccentric portion 410 and the connecting rod. This has the effect of expanding an oil path.
Additionally, as shown in FIG. 4B, a lower linear groove 710, having a predetermined width and depth, may be additionally formed at the outer circumferential surface of the eccentric portion 410 so that it extends from a lower end of the oil bank 600 to a lower end of the eccentric portion 410. The lower linear groove 710 allows the oil, which is supplied into the oil bank 600 through the connection path 560, to move downward along the eccentric portion 410. This expands the flow path of oil serving as a lubricant for the frictional region between the eccentric portion 410 and the connecting rod, and facilitates effective discharge of foreign substances.
Alternatively, a single spiral groove for moving oil formed at the outer circumferential surface of the eccentric portion. However, this spiral groove is designed to move oil in only a rotating direction of the rotating shaft due to a limitation in geometrical characteristics thereof. That is, oil is allowed to move upward in the spiral groove only when the spiral groove is formed in a direction opposite to the rotating direction of the rotating shaft. Unlike the spiral groove, the above-described linear grooves of the present invention are not affected by geometrical characteristics, and allow oil to move upon receiving a rotational centrifugal force of the rotating shaft, regardless of the rotating direction of the rotating shaft.
Referring to FIG. 4C, to allow the oil (which enters the oil bank 600 by the centrifugal force of the rotating shaft 400), to more effectively move to upper and lower portions of the eccentric portion 410, upper and lower inclined grooves 720 and 730 (serving as oil paths) may be formed above and beneath the oil bank 600. The upper groove 720 may be inclined in a direction opposite to the rotating direction of the rotating shaft 400 as designated by an arrow. The lower groove 730 may be inclined in the same direction as the rotating direction of the rotating shaft 400.
When oil moves along the upper and lower inclined grooves as stated above, the inclinations of the grooves provide resistance. Because the resistance of the path increases as the incline increases, a rotational centrifugal force of the rotating shaft can be used to overcome the increased resistance, resulting in a gradual reduction in the flow rate of the oil. Thus, it may be preferable to set an appropriate inclination of the grooves in consideration of the amount and flow rate of the oil and the stress applied to the frictional region.
Referring to FIGS. 5A to 5C, an oil supply structure according to a fourth non-limiting embodiment of the present invention is illustrated. Unlike the third embodiment in which oil is supplied into the oil bank via the connection path of the eccentric portion, oil may be supplied into the oil bank as it is scattered from the hollow portion to move downward into the oil bank according to the fourth non-limiting embodiment.
As shown in FIG. 5A, the eccentric portion 410 may be internally formed with the hollow channel 550 having an open upper end, so that oil moves upward to the upper end of the eccentric portion 410. Also, the oil bank 600 may have a circumferential groove form and may be formed at the outer circumferential surface of the eccentric portion 410 so that the oil moves along the oil bank 600.
Referring to FIG. 6, if the piston 230 reaches a top dead point (thereby reaching the maximum compression load), the maximum compression load may cause location (A) of the eccentric portion 410 to undergo maximum stress. Thus, it may be preferable to supply a sufficient amount of oil to location (A) because location (A) is most easily worn. Since location (A) is also where the rotational centrifugal force of the rotating shaft is applied to the maximum extent, the maximum amount of oil may be scattered and dropped via the hollow channel 550 so as to be gathered in location (A).
For this reason, in the present embodiment, a spiral groove 810 may be formed to extend from the upper end of the eccentric portion 410 to the upper end of the oil bank 600. Therefore, oil, which may be scattered and dropped from the hollow channel 550 of the eccentric portion 410, moves downward along the spiral groove 810 to sufficiently lubricate and cool the frictional region between the eccentric portion and the connecting rod. So that the oil smoothly moves downward along the spiral groove 810 regardless of the rotational centrifugal force of the rotating shaft 400, it may be preferable that the spiral groove 810 is inclined in the same direction as the rotating direction of the rotating shaft 400.
Referring to FIG. 5B, a lower spiral groove 820 may also be formed beneath location (A). The lower spiral groove 820 may be positioned beneath the oil bank 600 to extend from the lower end of the oil bank 600 to the lower end of the eccentric portion 410, so that the oil inside the oil bank 600 moves downward to the lower end of the eccentric portion 410. Through this configuration, lubrication of the contact region between the eccentric portion and the connecting rod may be easily achieved. The lower spiral groove 820 may expand the area of the oil path and may also be used as a discharge port for foreign substances, especially fine particulates. Preferably, the lower spiral groove 820 may also be inclined in the same direction as the rotating direction of the rotating shaft 400 to ensure that the oil smoothly moves downward along the spiral groove 820, regardless of the rotational centrifugal force of the rotating shaft 400.
Referring to FIG. 5C, to effectively disperse stress generated in the frictional region between the eccentric portion and the connecting rod, more particularly, generated at location (A), a groove 830 may be formed beneath the oil bank 600. The groove 830 may extend from a region, which may be spaced apart from location (A) by a predetermined distance, to the lower end of the eccentric portion. The lower groove 830 serves not only to expand the area of the oil path and to discharge foreign substances as stated above, but also to effectively disperse the stress applied to the eccentric portion, thereby achieving an improvement in the durability of the rotating shaft.
Referring to FIGS. 7A to 7C, an oil supply structure according to a fifth non-limiting, embodiment of the present invention is illustrated in sectional view. The fifth embodiment may include a connection path formed at the oil bank to communicate with the hollow channel of the eccentric portion, in addition to the configuration described with reference to FIGS. 5A to 5C.
With the present embodiment, oil may be scattered and dropped from the hollow channel 550 of the eccentric portion 410 by the centrifugal force of the rotating shaft, thereby causing the oil to move downward along the spiral groove. Remaining oil may enter the connection path 560 to move into the oil bank 600. Thereby, a sufficient amount of oil may be supplied to the frictional region between the eccentric portion 410 and the connecting rod, resulting in a reduction in wear of parts due to friction.
Referring to FIGS. 8A to 8C, a sixth non-limiting embodiment of the present invention is illustrated. The sixth non-limiting embodiment may be applied to any of the above-described embodiments. Specifically, the present embodiment may include two or three oil banks having the configurations described in the third to fifth embodiments. Accordingly, the number connection paths may be increased.
As shown in FIGS. 8A to 8C, the eccentric portion 410, as described in the third to fifth embodiments, may also be provided with a second oil bank 610. The second oil bank 610 may be located above the oil bank 600 and may include a circumferential groove formed at the outer circumferential surface of the eccentric portion 410. A second connection path 560 a may be formed at the second oil bank 610 to communicate with the hollow channel 550 of the eccentric portion 410. With this non-limiting exemplary configuration, a plurality of oil paths may be formed at the frictional region between the eccentric portion and the connecting rod to achieve satisfactory oil lubrication, which reduces wear in the compressor.
As apparent from the above description, the present invention provides an improved oil supply configuration in which an oil bank may be formed around an eccentric portion of a rotating shaft at a position of a connection path, thereby achieving more effective lubrication and cooling in a frictional region between the eccentric portion and a connecting rod. Such effective lubrication and cooling of the rotating shaft ensures a high reliability of the compressor.
In particular, oil gathered in the oil bank acts to smoothly lubricate contact surfaces of both the eccentric portion and the connecting rod when the compressor initially operates. Thereby, it is possible to prevent wear of the contact surfaces and to improve the performance of the compressor. Further, according to the present invention, an oil path may be formed at a lower region of the eccentric portion to discharge foreign substances, thereby preventing locking between the eccentric portion and the connecting rod.
Although embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in this embodiment without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.

Claims

1. A hermetic compressor, comprising:

a hermetic case;

a frame configured to be received in the hermetic case,

a drive unit and a compression unit arranged at lower and upper sides of the frame, respectively;

a rotating shaft mounted to the frame and configured to transmit a rotational force of the drive unit to the compression unit and having an upper eccentric portion connected to the upper compression unit; and

a connecting rod configured to be coupled to the eccentric portion,

wherein an oil bank is formed at a surface of the eccentric portion of the rotating shaft that comes into contact with the connecting rod.

2. The hermetic compressor according to claim 1, wherein the oil bank includes a circumferential groove formed at an outer circumferential surface of the eccentric portion.

3. The hermetic compressor according to claim 2, wherein the eccentric portion of the rotating shaft includes:

a hollow channel having an open upper end configured to scatter oil therefrom; and

a connection path formed in a radial direction of the eccentric portion to communicate with the hollow channel so that oil is supplied to at least one contact portion between the eccentric portion and the connecting rod.

4. The hermetic compressor according to claim 3, wherein the connection path is formed at the oil bank such that oil supplied into the connection path effectively remains in the oil bank.

5. The hermetic compressor according to claim 4, wherein a linear groove is formed at an outer circumferential surface of the eccentric portion to extend from an upper end of the oil bank to the upper end of the eccentric portion, thereby serving as an oil path to allow oil discharged from the connection path to move upward along the eccentric portion.

6. The hermetic compressor according to claim 5, wherein a linear groove is formed at the outer circumferential surface of the eccentric portion to extend from a lower end of the oil bank to a lower end of the eccentric portion, thereby serving as an oil path to allow the oil discharged from the connection path to move downward along the eccentric portion.

7. The hermetic compressor according to claim 4, wherein;

an upper inclined groove is formed above the oil bank to extend in a direction opposite to a rotating direction of the rotating shaft, and

a lower inclined groove is formed beneath the oil bank to extend in the rotating direction of the rotating shaft.

8. The hermetic compressor according to claim 2, wherein the eccentric portion includes:

a hollow channel having an open upper end to allow oil to be scattered therefrom; and

an inclined groove formed at an outer circumferential surface of the eccentric portion to extend from the upper end of the eccentric portion to an upper end of the oil bank in a rotating direction of the rotating shaft, thereby allowing the oil scattered from the upper end of the hollow channel to move downward to a location of the eccentric portion where a maximum centrifugal force is applied when a piston reaches a top dead point in a cylinder.

9. The hermetic compressor according to claim 8, wherein the eccentric portion further includes:

an inclined groove formed at the outer circumferential surface of the eccentric portion to extend from a lower end of the oil bank to a lower end of the eccentric portion in the same direction as the rotating direction of the rotating shaft, thereby allowing the oil remaining in the oil bank to move downward to the location of the eccentric portion where the maximum centrifugal force is applied when the piston reaches the top dead point in the cylinder.

10. The hermetic compressor according to claim 8, wherein the eccentric portion further includes:

an inclined groove formed at the outer circumferential surface of the eccentric portion to extend from a lower end of the oil bank to a lower end of the eccentric portion in the rotating direction of the rotating shaft, thereby enabling the oil remaining in the oil bank to move downward to a region which is spaced apart from the location of the eccentric portion where the maximum centrifugal force is applied when the piston reaches a top dead point in the cylinder.

11. The hermetic compressor according to any one of claims 8 to 10, wherein a connection path is formed in a radial direction of the eccentric portion to communicate with both the hollow channel and the oil bank, so that the oil is supplied to at least one contact region between the eccentric portion and the connecting rod.

12. The hermetic compressor according to claim 11, wherein the eccentric portion further includes a second oil bank, which includes a circumferential groove formed at the outer circumferential surface of the eccentric portion above the oil bank.

13. The hermetic compressor according to claim 12, wherein the eccentric portion further includes a second connection path formed in a radial direction of the eccentric portion to communicate with both the hollow channel and the second oil bank, so that the oil flowing in the hollow channel is introduced into the second oil bank.

14. The hermetic compressor according to any one of claims 5 to 8, wherein the eccentric portion further includes a second oil bank including a circumferential groove formed at the outer circumferential surface of the eccentric portion above the oil bank.

15. The hermetic compressor according to claim 14, wherein the eccentric portion further includes a second connection path formed in a radial direction of the eccentric portion to communicate with both the hollow channel and the second oil bank, so that the oil flowing in the hollow channel is introduced into the second oil bank.

16. A hermetic compressor, comprising:

a case;

a drive unit adapted to be received in the case;

a compression unit adapted to be received in the case;

a rotating shaft configured to transmit a rotational force of the drive unit to the compression unit, the rotating shaft including at least one eccentric portion;

a connecting rod adapted to be coupled to the at least one eccentric portion; and

an oil bank positioned at a surface of the at least one eccentric portion.

17. The hermetic compressor according to claim 16, wherein the oil bank is positioned at a surface of the at least one eccentric portion that contacts the connecting rod.

18. The hermetic compressor according to claim 16, further comprising a connection path formed at the at least one eccentric portion to supply oil to at least one contact portion between the at least one eccentric portion and the connecting rod.