Patent Application
20080080993
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:
Reference will now be made in detail to a hermetic compressor consistent with an exemplary embodiment of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The embodiment is described below to explain the present invention by referring to the figures.
Referring to
Provided within the hermetic container 10 are a compressing unit 20 to perform the compression of the refrigerant and a drive unit 30 to provide a drive force required for the compression of the refrigerant. The compressing unit 20 may be disposed on one side of a frame 40, and the drive unit may be disposed on an opposite side of the frame 40. Preferably, the compressing unit 20 is disposed on an upper side of the frame 40, and the drive unit 30 is disposed on a lower side of the frame 40. The frame 40 also preferably has a hollow central portion 41.
The drive unit 30 includes a stator 31 and a rotor 32 provided inside the stator 31. Preferably, the stator 31 is secured around the lower portion of the frame 40. The rotor 32 is adapted to rotate via electromagnetic interaction with the stator 31.
The compressing unit 20 includes a cylinder 21 defining a compressing chamber 21a therein, a piston 22 installed to perform a linearly reciprocating motion in the compressing chamber 21a so as to compress the refrigerant, a cylinder head 23 coupled to an end of the cylinder 21 so as to hermetically seal the compressing chamber 21a, and a valve device 24 provided between the cylinder 21 and the cylinder head 23. The cylinder head 23 has a refrigerant suction chamber 23b and a refrigerant discharge chamber 23a formed therein. The valve device 24 controls the flow of the refrigerant being suctioned from the refrigerant suction chamber 23b into the compressing chamber 21a or being discharged from the compressing chamber 21a into the refrigerant discharge chamber 23a. Preferably, the cylinder 21 is integrally formed with the frame 40 so as not to be separated from the frame 40. The cylinder 21 is also preferably disposed substantially adjacent to an upper side of the central hollow portion 41 of the frame 40.
The refrigerant suction chamber 23b serves to guide the refrigerant, introduced into the hermetic container 10 through the suction pipe 11, into the compressing chamber 21a. The refrigerant discharge chamber 23a is coupled to the discharge pipe 12.
A suction muffler 13 may be disposed within the hermetic container 10. The suction muffler 13 allows the refrigerant, introduced into the hermetic container 10 through the suction pipe 11, to be guided into the refrigerant suction chamber 23b with reduced pressure pulsations.
The drive force of the drive unit 30 is transmitted to the compressing unit 20 via a crankshaft 50. The crankshaft 50 includes a main shaft portion 51, an eccentric shaft portion 52, and a weight balance portion 53. The main shaft portion 51 has a portion rotatably disposed in the central hollow portion 41 of the frame 40 and an opposite portion coupled to the center of the rotor 32. The eccentric shaft portion 52 is preferably provided at an upper side of the main shaft portion 51 at an eccentric position relative to the main shaft portion 51. Preferably, the longitudinal axis 54 of the eccentric shaft portion 51 is not concentric with the longitudinal axis 55 of the main shaft portion 51. The weight balance portion 53 is disposed and adapted to compensate for a rotational imbalance caused by the eccentric rotation of the eccentric shaft portion 52. Preferably, the weight balance portion 53 is provided between the eccentric shaft portion 52 and the main shaft portion 51.
A connecting rod 60 couples the eccentric shaft portion 52 and the piston 22. The connecting rod 60 is adapted to convert a rotating motion of the crankshaft 50 into a linearly reciprocating motion of the piston 22.
Referring to
Preferably, the piston 22 and the connecting rod 60 are coupled to each other by use of a piston pin 22a. The piston 22 is formed to receive the small-diameter portion 62 of the connecting rod 60, and the small-diameter portion 62 is formed to receive the piston pin 22a. The piston 22 is also formed with holes 22c to receive the piston pin 22a. To couple the small-diameter portion 62 of the connecting rod 60 to the piston 22, the small-diameter portion 62 is inserted into the piston 22 and then the piston pin 22a is inserted into the holes 22c to pin the small-diameter portion 62 within the piston 22. A fixing pin 22b may be fastened in the piston 22 to secure the piston pin 22a at a fixed position.
Thus, when the rotor 32 rotates through electromagnetic interaction with the stator 31, the crankshaft 50 also rotates because it is coupled to the rotor 32. Because the eccentric shaft portion 22 is not concentric with the longitudinal axis 54 of the crankshaft 50, the eccentric shaft portion 22 moves in a path around the longitudinal axis 54 of the crankshaft 50. As the eccentric shaft portion 22 travels along its path, the eccentric shaft portion 22 alternately moves towards the cylinder 21 and away from the cylinder 21. Since the eccentric shaft portion 22 is coupled to the piston 22 via the connecting rod 60, the piston 22 is alternately pushed towards the cylinder 21 and pulled away from the cylinder 21. Thus, the piston 22 performs a linearly reciprocating motion in the compressing chamber 21a. Thereby, when the refrigerant is guided into the hermetic container 10 through the suction pipe 11, the refrigerant is suctioned into the compressing chamber 21a through the refrigerant suction chamber 23b of the cylinder head 23 and compressed in the compressing chamber 21a. After being compressed in the compressing chamber 21a, the refrigerant is discharged to the outside of the hermetic container 10 through the refrigerant discharge chamber 23a of the cylinder head 23 and the discharge pipe 12. Thus, the compressing unit 20 compresses the refrigerant by repeatedly suctioning, compressing, and discharging the refrigerant.
The crankshaft 50 is configured such that the eccentric shaft portion 52 of the crankshaft 50 is assembled with the piston 22 via the connecting rod 60 even though the cylinder 21 is integrally formed with the frame 40 and cannot be separated from the frame 40.
In the embodiment shown, the crankshaft 50 has a body 50A consisting of the weight balance portion 53 and the main shaft portion 51 preferably integrally formed with the weight balance portion 53. The eccentric shaft portion 52 is preferably formed separately from the body 50A. The eccentric shaft portion 52 is formed to couple, at a lower end thereof, to the weight balance portion 53 of the body 50A. Alternatively, the weight balance portion 53 and the main shaft portion 51 may be formed separately from each other and then assembled together.
Preferably, the eccentric shaft portion 52 is formed as a circular cylinder, and the weight balance portion 53 has a circular coupling recess 53a for receiving the lower end of the eccentric shaft portion 52. The circular coupling recess 53a is provided with a predetermined depth as measured relative to an upper surface of a side portion of the weight balance portion 53. To achieve a sufficient depth for the coupling recess 53a, a portion around the coupling recess 53a may have a thicker thickness than another portion of the weight balance portion 53.
Accordingly, a separately provided eccentric shaft portion 52 coupling to the weight balance portion 53 allows the eccentric shaft portion 52 to be assembled with the piston 22 via the connecting rod 60 even though the cylinder 21 is integrally formed with the frame 40 and cannot to be separated from the frame 40.
When the eccentric shaft portion 52 is rotatably coupled to the large-diameter portion 61 and is rotatably inserted in the coupling recess 53a, the eccentric shaft portion 52 may excessively rotate inside the large-diameter portion 61 and the coupling recess 53a. If the eccentric shaft portion 52 rotates excessively, the eccentric shaft 52 may be separated from the coupling recess 53a by vibrations, mechanical agitations, or other similar occurrences caused during the compression of the refrigerant, or may unintentionally slip within the large-diameter portion 61 in the course of compressing the refrigerant. Accordingly, it is preferable to prevent relative rotation between the eccentric shaft portion 52 and the large-diameter portion 61.
To prevent relative rotation between the eccentric shaft portion 52 and the large-diameter portion 61, the eccentric shaft portion 52 preferably has a pair of restraint protrusions 52a protruding radially from an outer surface of an upper portion thereof. Also, the large-diameter portion 61 has restraint grooves 61a formed in an inner periphery thereof. The restraint grooves 61a allow the restraint protrusions 52a to be inserted thereinto from the upper side of the restraint grooves 61a. Since the restraint protrusions 52a are restrained by the restraint grooves 61a, relative rotation between the eccentric shaft portion 52 and the large-diameter portion 61 is prevented. The configuration for preventing the relative rotation of the eccentric shaft portion 52 and the large-diameter portion 61 may be accomplished by other various methods, for example, by press-fitting the eccentric shaft portion 52 to the inner periphery of the large-diameter portion 61.
Referring to
Accordingly, the eccentric shaft portion 52 can be coupled to the large-diameter portion 61 of the connecting rod 60 without lifting the large-diameter portion 61 of the connecting rod 60 over the eccentric shaft portion 52 when the piston 22, coupled to the small-diameter portion 62, is already in the compressing chamber 21a. Thus, the assembling of the eccentric shaft portion 52 and the piston 22 to the connecting rod 60 is facilitated. Additionally, when the eccentric shaft portion 52 is assembled to the large-diameter portion 61 in the above described manner, the large-diameter portion 61 does not require an inner diameter larger than an outer diameter of the eccentric shaft portion 52, thus a bushing that is normally interposed between the eccentric shaft portion and the large-diameter portion in the conventional hermetic compressor can be omitted. Therefore, the number of constituent elements of the hermetic compressor is reduced.
As described above, the eccentric shaft portion 52 is configured as a separate element and rotatably inserted into the coupling recess 53a. This configuration provides a tolerance between the coupling recess 53a and the eccentric shaft portion 52. The tolerance allows the eccentric shaft portion 52 to be inserted into the coupling recess 53a after the large-diameter portion 61 is aligned with the eccentric shaft portion 52. Thus, the coupling of the eccentric shaft portion 52 to the connecting rod 60 is facilitated.
As apparent from the above description, the present invention provides a hermetic compressor in which an eccentric shaft portion for a crankshaft is separately provided and rotatably coupled to a weight balance portion of the crankshaft. The coupling of the eccentric shaft portion and the weight balance portion is accomplished while assembling the eccentric shaft portion and a piston to a connecting rod. The hermetic compressor consistent with the present invention simplifies the assembling of the piston and the eccentric shaft portion via the connecting rod even when a cylinder is integrally formed with a frame and cannot be separated from the frame.
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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2006-0096862 | Oct 2006 | KR | national |
