This application claims the benefit of Korean Application No. 2003-50668, filed Jul. 23, 2003, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates, in general, to variable capacity rotary compressors and, more particularly, to a variable capacity rotary compressor, which is designed to apply a same pressure to upper and lower ends of a roller placed in a compression chamber having a lower pressure, thus allowing the roller to be smoothly rotated.
2. Description of the Related Art
Generally, a compressor is installed in a refrigeration system, such as an air conditioner and a refrigerator, which functions to cool air in a given space using a refrigeration cycle. In the refrigeration system, the compressor functions to compress a refrigerant which circulates through a refrigeration circuit of the refrigeration system. A cooling capacity of the refrigeration system is determined according to a compression capacity of the compressor. Thus, when the compressor is constructed to vary the compression capacity thereof as desired, the refrigeration system may be operated under an optimum condition, according to a difference between an environmental temperature and a preset reference temperature, thus allowing air in a given space to be efficiently cooled, and saving energy.
In the refrigeration system have been used a variety of compressors, for example, rotary compressors, reciprocating compressors, etc. The present invention relates to the rotary compressor, which will be described in the following.
The conventional rotary compressor includes a hermetic casing, with a stator and a rotor being installed in the hermetic casing. A rotating shaft penetrates through the rotor. An eccentric cam is integrally provided on an outer surface of the rotating shaft. A roller is provided in a compression chamber to be fitted over the eccentric cam. The rotary compressor constructed as described above is operated as follows. As the rotating shaft rotates, the eccentric cam and the roller execute eccentric rotation in the compression chamber. At this time, a gas refrigerant is drawn into the compression chamber and then compressed, prior to discharging the compressed refrigerant to an outside of the hermetic casing.
However, the conventional rotary compressor has a problem in that the rotary compressor is fixed in a compression capacity thereof, so that it is impossible to vary the compression capacity according to a difference between an environmental temperature and a preset reference temperature.
In a detailed description, when the environmental temperature is considerably higher than the preset reference temperature, the compressor must be operated in a large capacity compression mode to rapidly lower the environmental temperature. Meanwhile, when the difference between the environmental temperature and the preset reference temperature is not large, the compressor must be operated in a small capacity compression mode so as to save energy. However, it is impossible to change the capacity of the rotary compressor according to the difference between the environmental temperature and the preset reference temperature, so that the conventional rotary compressor does not efficiently cope with a variance in temperature, thus leading to a waste of energy.
Accordingly, it is an aspect of the present invention to provide a variable capacity rotary compressor, which is constructed so that a compression operation is executed in either of two compression chambers having different capacities, thus varying a compression capacity as desired.
It is another aspect of the present invention to provide a variable capacity rotary compressor, which is designed to make a pressure of a high-pressure side be uniformly applied to upper and lower ends of a roller of a low-pressure side, thus allowing the roller of the low-pressure side to be smoothly rotated.
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.
The above and/or other aspects are achieved by providing a variable capacity rotary compressor including a housing, a rotating shaft, first and second eccentric units, and first and second rollers. The housing defines first and second compression chambers therein which are partitioned by a partition plate. First and second flanges are mounted to predetermined positions of the first and second compression chambers to close openings of the first and second compression chambers, respectively. The rotating shaft passes through the first and second compression chambers and the partition plate. The first and second eccentric units are mounted to the rotating shaft to be placed in the first and second compression chambers, respectively. One of the first and second eccentric units is eccentric from the rotating shaft to execute a compression operation while a remaining one of the first and second eccentric units is released from eccentricity from the rotating shaft to execute an idle rotation according to a rotating direction of the rotating shaft. The first and second eccentric units are oppositely operated. The first and second rollers are fitted over the first and second eccentric units, respectively, with inside portions of ends of the first and second rollers being spaced apart from inside surfaces of the first and second flanges, respectively, thus offsetting pressure applied to the ends of the first and second rollers.
An annular depression is provided on the inside surface of each of the first and second flanges, thus allowing the first and second flanges to be spaced apart from the ends of the first and second rollers.
The partition plate has a through hole at a center thereof. The through hole has a larger diameter than the rotating shaft to allow the rotating shaft to pass through the partition plate, and the annular depression has an inner diameter equal to an inner diameter of the through hole.
The first and second eccentric units include first and second eccentric cams mounted to an outer surface of the rotating shaft to be placed in the first and second compression chambers, respectively, and first and second eccentric bushes rotatably fitted over the first and second eccentric cams, respectively, with the first and second rollers fitted over the first and second eccentric bushes, respectively. The first and second eccentric units also include a locking unit to make one of the first and second eccentric bushes be eccentric from the rotating shaft while making a remaining one of the first and second eccentric bushes be released from eccentricity from the rotating shaft, according to a rotating direction of the rotating shaft.
The compressor also includes a cylindrical connecting part to connect the first and second eccentric bushes to each other while the first and second eccentric bushes are eccentric in opposite directions. The locking unit includes a locking slot provided around the connecting part, and a locking pin mounted to the rotating shaft to engage with the locking slot.
The above and/or other aspects and advantages of the invention will become apparent and more readily appreciated from the following description of the preferred embodiments, taken in conjunction with the accompanying drawings of which:
Reference will now be made in detail to the present preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.
As illustrated in
The compressing unit 30 includes upper and lower housings 33a and 33b which define first and second compression chambers 31 and 32, respectively. The first and second compression chambers 31 and 32 are both cylindrical but have different capacities. An upper flange 35 is mounted to an upper surface of the upper housing 33a to close an upper portion of the first compression chamber 31, and a lower flange 36 is mounted to a lower surface of the lower housing 33b to close a lower portion of the second compression chamber 32. Further, the upper and lower flanges 35 and 36 function to rotatably support the rotating shaft 21. A partition plate 34 is interposed between the upper and lower housings 33a and 33b to partition the first and second compression chambers 31 and 32 into each other.
As illustrated in
The first and second eccentric units 40 and 50 include first and second eccentric cams 41 and 51, respectively. The first and second eccentric cams 41 and 51 are mounted to an outer surface of the rotating shaft 21 to be placed in the first and second compression chambers 31 and 32, respectively, while being eccentric from the rotating shaft 21 in a same direction. First and second eccentric bushes 42 and 52 are rotatably fitted over the first and second eccentric cams 41 and 51, respectively. As illustrated in
As illustrated in
That is, when the rotating shaft 21 is rotated while the locking pin 81 mounted to the eccentric part 44 of the rotating shaft 21 engages with the locking slot 82 of the connecting part 43, the locking pin 81 is rotated within the locking slot 82 to be locked by either of locking parts 82a and 82b which are provided at opposite ends of the locking slot 82, thus making the first and second eccentric bushes 42 and 52 be rotated along with the rotating shaft 21. Further, when the locking pin 81 is locked by either of the locking parts 82a and 82b of the locking slot 82, one of the first and second eccentric bushes 42 and 52 is eccentric from the rotating shaft 21 and a remaining one of the first and second eccentric bushes 42 and 52 is released from eccentricity from the rotating shaft 21, thus executing a compression operation in one of the first and second compression chambers 31 and 32 and executing an idle operation in a remaining one of the first and second eccentric bushes 42 and 52. On the other hand, when a rotating direction of the rotating shaft 21 is changed, the first and second eccentric bushes 42 and 52 are arranged oppositely to the above-mentioned state.
According to the variable capacity rotary compressor of
As illustrated in
As illustrated in
The path control unit 70 includes a hollow cylindrical body 71, and a valve unit installed in the body 71. An inlet 72 is provided at a central portion of the body 71 to be connected to the refrigerant inlet pipe 69. First and second outlets 73 and 74 are provided on opposite sides of the body 71. Two pipes 67 and 68, which are connected to the inlet port 63 of the first compression chamber 31 and the inlet port 64 of the second compression chamber 32, respectively, are connected to the first and second outlets 73 and 74, respectively. Further, the valve unit includes a valve seat 75, first and second valve members 76 and 77, and a connecting member 78. The valve seat 75 has a cylindrical shape, and is opened at both ends thereof. The first and second valve members 76 and 77 are installed on both sides in the body 71, and axially reciprocate in the body 71 to open or close both ends of the valve seat 75. The connecting member 78 connects the first and second valve members 76 and 77 to each other to allow the first and second valve members 76 and 77 to move together. In light of the above configuration, the path control unit 70 is operated as follows.
When the compression operation is executed in either of the first and second compression chambers 31 and 32, the first and second valve members 77 set in the body 71 move in a direction toward one of the two outlets 73 and 74 having a lower pressure due to a difference in pressure between the two outlets 73 and 74, thus automatically changing the refrigerant intake path. For example, the refrigerant intake path is formed to draw the refrigerant into the inlet port of a compression chamber where the compression operation is executed.
The operation of the variable capacity rotary compressor according to the present invention will be described below.
As illustrated in
The compressor of the present invention is operated as described above, because the first and second eccentric cams 41 and 51 are eccentric from the rotating shaft 21 in a same direction while the first and second eccentric bushes 42 and 52 are eccentric from the rotating shaft 21 in opposite directions. That is, when a maximum eccentric part of the first eccentric cam 41 and a maximum eccentric part of the first eccentric bush 42 are arranged in a same direction, a maximum eccentric part of the second eccentric cam 51 and a maximum eccentric part of the second eccentric bush 52 are arranged in opposite directions, thus allowing the compressor of the present invention to be operated as described above.
When the compression operation is executed in the first compression chamber 31 and the idle rotation is executed in the second compression chamber 32, as illustrated in
When the rotating shaft 21 is rotated in a direction opposite to the direction of
When the compression operation is executed in the second compression chamber 32, the path control unit 70 controls the refrigerant intake path to draw the refrigerant into the inlet port 64 of the second compression chamber 32. When the compression operation is executed in the second compression chamber 32 and the idle rotation is executed in the first compression chamber 31, as illustrated in
As is apparent from the above description, the present invention provides a variable capacity rotary compressor, which is designed to execute a compression operation in either of first and second compression chambers having different capacities by an eccentric unit which rotates in the first or second direction, thus varying a compression capacity of the compressor as desired.
Further, the present invention provides a variable capacity rotary compressor, which is designed to make a pressure of a high-pressure side be applied to an end of a roller of a low-pressure side through an annular depression formed on an inside surface of each of upper and lower flanges. Thus, pressure of an equal magnitude is applied to upper and lower ends of the roller executing an idle rotation, so that the pressure applied to the upper end of the roller is offset by the pressure applied to the lower end of the roller. Therefore, the roller executing the idle rotation is prevented from coming into close contact with the upper or lower flange, or being inclined. As a result, the roller executing the idle rotation is smoothly rotated.
Although a preferred embodiment of the present invention has been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments 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 |
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2003-50668 | Jul 2003 | KR | national |