In general, a compressor is an apparatus for compressing fluid, and divided into a rotary compressor, a reciprocating compressor, and a scroll compressor according to a compressing method.
FIG. 1 is showing an embodiment of a hermetic rotary compressor among those compressors. In the hermetic rotary compressor, when a driving motor 20 which is installed on a sealed chamber is operated, a rotating axis 30 which is coupled to a rotor 21 of the driving motor 20 is rotated, and then an eccentric part 31 on the rotating axis 30 is eccentrically rotated in a compression space P of a cylinder 40 located on lower part of the driving motor 20.
The eccentric part 31 of the rotating axis 30 is rotated in the compression space P of the cylinder 40, accordingly, a rolling piston 45 which is coupled to the eccentric part 31 is line contacted to the cylinder 40, and the rolling piston 45 performs circular movement in the compression space P of the cylinder 40 in the state that it is line contacted to a vane (not shown) which is coupled to the cylinder 40 slidably.
The rolling piston 45 performs circular movement in the compression space P of the cylinder 40, and accordingly, the compression space P of the cylinder 40 which is divided by the vane (not shown) is partitioned into a compression area and a suction area. In addition, the refrigerant gas is sucked through a suction port 41 installed in the cylinder 40 and compressed, and discharged through a discharge port 42 disposed on one side of the cylinder 40. And then the compressed refrigerant gas is discharged to inside of the sealed chamber 10 through a discharge hole 51 formed on an upper bearing 50 between two bearings, that is, an upper bearing 50 and a lower bearing 60 which are coupled to both sides of the cylinder 40 as covering the cylinder 40.
At that time, a discharge valve 52 which is coupled to upper part of the upper bearing 50 opens/closes the discharge hole 51 corresponding to changing of the compression space P of the cylinder 40 into the compression area and the discharge area.
In addition, the compressed refrigerant gas discharged into the sealed chamber 10 flows through the inside of the sealed chamber 10, and is discharged to outer side of the sealed chamber 10 through a discharge tube 70 which is coupled to upper part of the sealed chamber 10. At that time, some of lubricant for lubricating driven parts in the sealed chamber 10 is discharged together with the compressed refrigerant gas.
On the other hand, as the processes of sucking, compressing, and discharging the refrigerant gas in the compression space P of the cylinder 40 are repeated, a severe noise is generated because of pressure pulsation of the refrigerant gas which is discharged from the compression space P of the cylinder 40 and of an impact noise generated during opening/closing the discharge valve 52, and therefore a muffler F is installed so as to minimize the noise.
The muffler is installed on one of the upper bearing 50 or the lower bearing 60 coupled to upper and lower parts of the cylinder 40, through which the compressed refrigerant gas is discharged, and the muffler F is installed on the upper bearing 50 is shown in FIG. 1.
Unexplained reference numeral 22 designates a stator, and 61 designates a bolt for coupling.
On the other hand, FIGS. 2 and 3 are showing an embodiment of the muffler (hereinafter, referred to as the first muffler) which is installed on the conventional hermetic rotary compressor.
As shown therein, the first muffler comprises: a muffler body 80 formed as a cap so as to cover upper part of the upper bearing 50; a plurality of bolt coupling parts contacted to upper surface of the upper bearing 50 and depressed as certain area on upper circumference of the muffler body 80 so that a coupling bolt 61 can be coupled; and a penetrating hole 82, through which a part of the upper bearing 50 is penetrated, on upper central part of the muffler body 80; a convex part 83 relatively protruded by the bolt coupling part 81 and having inner space.
In addition, two discharge ports 84 are formed on upper part of the muffler body 80, and a bending tube 85 having a predetermined length is coupled inside the muffler body 80 so as to communicate with the discharge ports 84. In addition, the bending tube 85 is located so as to be in a line with a circular arc direction on the outer circumferential surface of the muffler body 80.
The first muffler is coupled by the coupling bolt 61 so as to cover the upper bearing (or the lower bearing), and the refrigerant gas discharge through the discharge hole 51 of the upper bearing 50 goes through muffling space formed by the bolt coupling part 81 and the convex part 83 of the upper bearing 50 and then discharged to the inner part of the sealed chamber 10 through the bending tube 85 and the discharge port 84. Therefore, the noise generated by the pressure pulsation and by the opening/closing the valve can be reduced.
On the other hand, FIGS. 4 and 5 are showing another embodiment of the conventional muffler (hereinafter, referred to as the second muffler) installed on the hermetic rotary compressor.
As shown therein, the second muffler comprises: a muffler body 90 formed as a cap so as to cover upper part of the upper bearing 50; a plurality of bolt coupling parts 91 depressed as a certain area on upper circumference of the muffler body 90 so as to being contacted to upper surface of the upper bearing 50 and being coupled to the coupling bolt; a penetrating hole 92, through which a part of the upper bearing 50 is penetrated and inserted, on upper central part of the muffler body 90; and a convex part 93 relatively protruded by the bolt coupling part 91 and having inner space.
In addition, two discharge ports 94 are formed on upper surface of the convex part 93 of the muffler body 91, and a pair of upper/lower covers 95 and 96 of hemisphere or half-elliptic shape which cover more than half of the discharge port 94. In addition, fluid passages formed by the upper and lower covers 95 and 96 which cross each other are located so as to be in line with the circular arc direction on outer circumferential surface of the muffler body 90.
The second muffler is coupled by the coupling bolt 61 so as to cover the upper bearing (or the lower bearing), and the compressed refrigerant gas which is discharged through the discharge hole 51 of the upper bearing 50 goes through muffling spaces formed by the bolt coupling part 91 of the convex part 93 of the upper bearing 50 and then discharged to inner side of the sealed chamber 10 through the discharge port 94 and the upper/lower covers 95 and 96. Therefore the noise generated by the pressure pulsation and the valve opening/closing can be reduced.
On the other hand, the noise generated during the processes of sucking, compressing, and discharging the refrigerant gas in the compression space P of the cylinder 40 is generated because the refrigerant gas which is compressed in the compression space P of the cylinder 40 is discharged to the inner side of the sealed chamber having large inner volume through the discharge hole 51 having relatively small diameter.
Therefore, in the first and second mufflers which are covered by the upper bearing 50 including the discharge hole 51, the refrigerant gas of high pressure which is discharged through the discharge hole 51 goes through the muffling spaces of the first and second muffler, and the bending tube or the fluid passage formed by the upper/lower covers 95 and 96, and then the noise is reduced. In addition, the arrow line shown in FIGS. 2 and 4 represents the flowing of the refrigerant gas which flows inside the muffler.
However, the noise is generated while the refrigerant gas of high pressure is discharged to inner side of the sealed chamber 10 through the muffling spaces, the bending tube 85 which is located so as to be in line with the circular arc direction of the outer circumferential surface, and the discharge port 84. In addition, the passage resistance is increased in the process of flowing the refrigerant gas of high pressure through the bending tube 85, and therefore the inputted electric source is increased. Also, the bending tube 85 is coupled to inner side of the muffler body 80 so as to communicate with the discharge port 84, and therefore the structure is complex and assembling process becomes difficult.
On the other hand, the refrigerant gas of high pressure discharged through the discharge hole 51 of the upper bearing passes through the muffling spaces and is discharged to the inside of the sealed chamber 10 through the discharge port 94 which forms the passage so as to be in line with the circular arc direction on the outer circumferential surface of the muffler body 90, and through between the upper and lower covers 95 and 96, and the noise is generated during the processes. Also, the upper cover 95 and the lower cover 96 are coupled to inner upper side and to outer upper side of the muffler body 90 so as to cover the discharge port 94, and therefore the structure is complex and assembling process becomes difficult.
Also, in case of the first and second mufflers, the bending tube 85 and the upper/lower covers 95 and 96 are formed so as to be in line with the circular arc direction on the outer circumferential surface of the muffler body 80 and 90, that is, so as to be corresponded with the flowing direction of the refrigerant gas, and therefore, the pulsation noise of the refrigerant gas and the impact noise of the valve is transmitted to the inner side of the sealed chamber 10.
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