KR20120081490A - Scroll compressor with split type orbitting scroll - Google Patents

Abstract

The present invention relates to a scroll compressor having a separate swing scroll, according to one aspect of the invention, the case; A fixed scroll installed in the case; A wrap part engaged with the fixed scroll to form a compression chamber; A base portion to move the wrap portion to the fixed scroll side; A driving motor coupled to a rear surface of the base part to eccentrically rotate the base part and the wrap part; And a main frame supporting the base part and installed in the case, wherein a back pressure chamber communicating with the compression chamber is formed between the wrap part and the base part.

Description

SCROLL COMPRESSOR WITH SPLIT TYPE ORBITTING SCROLL}

The present invention relates to a scroll compressor having a separate swing scroll, and more particularly to a scroll compressor in which the swing scroll is rotated with respect to the fixed scroll.

Generally, a scroll compressor is a compressor which compresses refrigerant gas by changing the volume of the compression chamber formed by a pair of opposing scrolls. Scroll compressors are more efficient than reciprocating compressors or rotary compressors, have low vibration and noise, are compact and lightweight, and thus are widely used in air conditioners.

The scroll compressor may be classified into a low pressure type and a high pressure type according to the type of refrigerant supplied to the compression chamber. That is, in the low pressure scroll compressor, the refrigerant is indirectly sucked into the compression chamber through the inner space of the casing, and the inner space of the casing is divided into the suction space and the discharge space. On the other hand, in the high pressure scroll compressor, the refrigerant is directly supplied to the compression chamber without passing through the inner space of the casing and then discharged into the inner space of the casing, and the entire inner space of the casing is a discharge space.

The scroll compressor may also be classified into a tip seal method and a back pressure method by a sealing method of a compression chamber. That is, the tip seal method is a method in which a tip seal is installed at the lap end of each scroll so that the tip seal floats while the compressor is in operation and is in close contact with the hard plate portion of the opposite scroll. On the other hand, in the back pressure method, a back pressure chamber is formed on the rear surface of one scroll and the oil or refrigerant of medium pressure is induced in the back pressure chamber so that the scroll is pressed against the opposite scroll by being pushed by the pressure in the back pressure chamber. Generally, the tip seal method is applied to a low pressure scroll compressor, while the back pressure method is applied to a high pressure scroll compressor.

On the other hand, the rotating shaft of the drive motor is coupled to one side of the turning scroll, the other side is formed with a wrap engaging the fixed scroll. In particular, in the case of the turning scroll, both sides are rotated in contact with the fixed scroll and the main frame, respectively, and thus, it is necessary to precisely process the shape in order to suppress vibration and minimize the loss due to friction. To this end, the turning scroll is to process the wrap portion after the machining of the bearing surface in contact with the main frame, due to this there is a risk that the bearing surface is damaged in the process of the longer working time and the wrap portion. In addition, since the shape of the swing scroll and the fixed scroll, in particular the shape and size of the wrap portion according to the capacity of the compressor to be different, it takes a considerable time to design and manufacture the swing scroll.

In addition, the pressure of the bearing surface of the turning scroll presses the bearing surface of the fixed scroll varies according to the pressure applied to the back pressure chamber. In order to prevent leakage of the refrigerant and to reduce frictional force, the pressure applied to the back pressure chamber must be maintained appropriately. do. However, in the case of the conventional scroll compressor, since the entire swing scroll must be supported by the pressure in the back pressure chamber, a considerable amount of high pressure must be applied to the back pressure chamber, and if the pressure in the back pressure chamber changes, the adhesion force of the swing scroll to the fixed scroll is changed. There is a problem that greatly affects. In particular, the pressure in the back pressure chamber is influenced by the discharge pressure. Since the discharge pressure varies depending on the load applied to the compressor, the sealing performance and frictional loss between the swing scroll and the fixed scroll may be affected by the load fluctuation. There was a problem.

The present invention is to provide a scroll compressor that can achieve a sufficient sealing performance while minimizing frictional losses between the swing scroll and the fixed scroll even if there is a load variation.

According to an aspect of the present invention for achieving the above technical problem, a case; A fixed scroll installed in the case; A wrap part engaged with the fixed scroll to form a compression chamber; A base portion to move the wrap portion to the fixed scroll side; A driving motor coupled to a rear surface of the base part to eccentrically rotate the base part and the wrap part; And a main frame supporting the base part and installed in the case, wherein a back pressure chamber communicating with the compression chamber is formed between the wrap part and the base part.

In the above aspect of the present invention, the rotating scroll is configured to be separated from the base portion, so that the wrap portion and the base portion can be manufactured separately. Through this, the base part can be shared by many compressors of different capacities, thereby making it easier to manufacture the turning scroll. In addition, a back pressure chamber is formed between the wrap part and the base part so that only the wrap part, not the entire swing scroll, comes into close contact with the fixed scroll side. To prevent leakage.

Here, the base portion is a boss coupled to the rotating shaft of the drive motor; And a base flange facing the wrap portion, wherein the back pressure chamber may be formed on the base flange.

A sealing means for sealing the back pressure chamber may be interposed between the base flange and the wrap part.

On the other hand, the wrap section wrap wrap facing the base portion; And a turning wrap engaged with the fixed wrap of the fixed scroll; and a back pressure hole communicating the back pressure chamber and the compression chamber may be formed through the wrap flange. Through this, since the length of the back pressure hole can be shortened, not only the loss of back pressure can be minimized, but also the back pressure hole can be easily processed.

The back pressure hole may be formed at a position such that both the discharge pressure and the intermediate pressure defined as a value between the discharge pressure and the suction pressure may be applied to the back pressure chamber. Due to the operation principle of the scroll compressor, the pressure applied to the compression chamber is continuously changed. Specifically, at the outermost sides of the fixed wrap and the swing wrap, the pressure corresponding to the suction pressure gradually increases to have an intermediate pressure. Discharge occurs while reaching pressure. In addition, since the pressure chamber has a form extending in the circumferential direction similar to the crescent moon, the pressure at a specific position of the turning scroll also changes.

Depending on the position, both the intermediate pressure and the discharge pressure may be applied. When the back pressure hole is formed at this position, the intermediate pressure is initially applied to the back pressure chamber, and the discharge pressure is also applied while the turning wrap is rotated. Therefore, the pressure interlocked with the compression chamber is applied to the back pressure chamber. In other words, when the pressure in the compression chamber is low, there is less risk of leakage. Therefore, it is advantageous to reduce the loss due to friction by lowering the back pressure, and when the pressure in the compression chamber is high, the risk of leakage is relatively high. It is necessary to block the leakage by increasing the, it is possible to properly adjust the back pressure through the configuration as described above.

Specifically, when the discharge start time of the turning wrap is α, the back pressure hole may be located at a point having a phase angle larger than α and smaller than α + 180 ° on the turning wrap.

Meanwhile, the wrap part and the base part may be key-coupled, and a key may be integrally formed on one side of the wrap part and the base part, and a key hole may be formed on the other side.

The case may be divided into two spaces having different pressures, and the wrap part and the base part may be disposed in a space having a relatively low pressure among the two spaces. In this case, the case may be partitioned into two spaces having different pressures by the fixed scroll.

According to another aspect of the invention, the fixed scroll; A swing scroll including a swing wrap for forming a compression chamber together with the fixed scroll, and coupling means for movably supporting the swing wrap toward the fixed scroll; And pressurizing means positioned on the rear surface of the swing wrap and generating a back pressure for introducing a part of the working fluid of the compression chamber to move the swing wrap to the fixed scroll side.

Here, the pressing means is located on the rear surface of the swing wrap, and includes a back pressure chamber having a pressure higher than the pressure on the outer peripheral side of the swing wrap, the back pressure chamber and the compression chamber may be in communication with each other.

In addition, a back pressure hole communicating the back pressure chamber and the compression chamber may be formed in the swing scroll.

According to the aspects of the present invention having the configuration as described above, by separating the swing scroll into two parts can achieve a sufficient degree of sealing even at a relatively low back pressure, which varies depending on the operating conditions such as load Since the lower pressure can be used as the back pressure instead of the discharge pressure, the compressor can be driven more stably.

1 is a cross-sectional view showing a first embodiment of a scroll compressor according to the present invention.
FIG. 2 is an enlarged partial cutaway view of the compression mechanism of FIG. 1.
3 is an exploded perspective view showing the turning scroll in FIG.
4 is an enlarged cross-sectional view of the turning scroll in FIG. 1.
5A to 5C are plan views schematically illustrating a process in which the first embodiment shown in FIG. 1 operates.
6 is a graph showing the magnitude of the axial force according to the position of the back pressure hole formed in the turning scroll in FIG.
7 is a sectional view showing a second embodiment of a scroll compressor according to the present invention.

Hereinafter, the scroll compressor according to the present invention will be described in detail with reference to the embodiments shown in the accompanying drawings.

1 is a longitudinal sectional view showing a first embodiment of a scroll compressor according to the present invention, Figure 2 is a partial cutaway view showing the assembly state of the compression mechanism in the scroll compressor according to Figure 1, Figure 3 is a scroll according to Figure 1 An exploded perspective view showing the turning scroll in the compressor.

As shown in Figures 1 to 3, the scroll compressor according to the present invention, the inner space of the case 1 is divided into a suction space 11 of the low pressure portion and the discharge space 12 of the high pressure portion, the case (1) A driving motor 2 for generating a rotational force is installed in the suction space 11 of the), and the main frame 3 is fixedly installed between the suction space 11 and the discharge space 12 of the case 1. A fixed scroll 4 is fixedly installed on an upper surface of the main frame 3, and is eccentrically coupled to the crank shaft 23 of the drive motor 2 between the main frame 3 and the fixed scroll 4. The swinging scroll 5 which forms two pairs of compression chambers P which move continuously with the fixed scroll 4 is installed so that rotation is possible. In addition, an old dam ring 6 is installed between the fixed scroll 4 and the revolving scroll 5 to prevent the revolving movement of the revolving scroll 5.

The suction tube 13 is coupled to the suction space 11 of the case 1 while the discharge tube 14 is coupled to the discharge space 12.

Here, although not shown in the drawings, the case is provided with a predetermined discharge space sealed and the suction space is a low pressure portion and the discharge space is a high pressure portion by a discharge plenum fixedly coupled to the fixed scroll (4), or The inner space of the case may be divided into a suction space and a discharge space by a high and low pressure separator (not shown) fixed to an upper surface of the fixed scroll and in close contact with an inner circumferential surface of the case.

The fixed scroll (4) is projected on the bottom surface of the hard plate portion 41 is formed with a fixed wrap 42 in the involute shape to form a compression chamber (P) together with the turning wrap (52) of the turning scroll (5). . A suction port (not shown) is formed on the outer circumferential surface of the hard plate portion 41 of the fixed scroll 4 so that the suction space 11 and the compression chamber P of the case 1 communicate with each other. A discharge port 44 is formed in the center of the hard plate part 41 so that the compression chamber P and the discharge space 12 of the case 1 communicate with each other. In the figure, 7 is a subframe, 8 is a discharge valve, 21 is a stator, and 22 is a rotor.

Therefore, in the above embodiment, the refrigerant flows from the outside into the suction space 11, which is the low pressure portion of the case 1, through the suction pipe 13, and the low pressure refrigerant in the suction space 11 is the suction port of the fixed scroll 4. It is introduced into the discharge space 12 of the case (1) through the discharge port 44 of the fixed scroll (4) is compressed while moving to the center of the rotating scroll and the fixed scroll by the turning scroll (5) The process of discharge is repeated.

On the other hand, the turning scroll 5 is configured to be separated into two parts, as shown in Figures 2 and 3, specifically, the wrap portion 50 and the wrap portion 50 meshing with the fixed scroll, respectively It is composed of a base portion 60 coupled to. The wrap portion 50 is configured to include a swing wrap 52 which is engaged with the fixed wrap 42 to form a compression chamber and a wrap flange 54 which is integrally formed with the swing wrap 52. The wrap flange 54 has a disc shape, and key shapes 56 are formed at both sides of the bottom surface to be coupled with the base 60.

The base portion 60 is coupled to the wrap portion 50 in a state facing the bottom surface of the wrap flange 54, specifically, the base flange 64 is formed to have a disk shape similar to the wrap flange 54 And a boss portion 68 formed on the bottom surface of the base flange 64 to be coupled to the crankshaft 23 described above.

In addition, keyholes 66 for fastening with the key-shaped portion 56 are formed at both edges of the upper surface of the base flange 64. The lap portion 50 is movable in the axial direction of the crankshaft relative to the base portion 60 by being inserted into the keyhole, but is coupled such that the key portion is not movable in the radial or circumferential direction of the base portion. do. However, since the axial movement of the wrap part 50 is limited by the distance between the fixed scroll and the main frame 3, the key shape 56 is inserted into the key hole 66. Will be maintained. That is, the two can be stably coupled by simply inserting the key shape into the key hole without using a method such as bolting or welding.

In addition, the Oldham ring 6 as the anti-rotation mechanism described above is coupled to the bottom of the base portion 60. Specifically, the old dam ring 6 includes a ring-shaped portion 6a that is in contact with the bottom surface of the base flange 64, and both sides of the ring-shaped portion 6a have a phase difference of 180 degrees. First projections 6b are formed. The first protrusion 6b is inserted into the first protrusion groove 3a formed in the main frame 3. In addition, two second protrusions 6c are formed on both sides of the upper surface of the ring-shaped portion 6b in the state of having a phase difference of 180 degrees. The second protrusion 6c is inserted into the second protrusion grooves 64a respectively formed on the bottom surface of the base flange 64.

Through this, even if the rotational force of the crankshaft 23 is transmitted to the base portion 60, the base portion 60 is rotated by the old dam ring 6 in a state where the rotation is prevented, the base portion Wrap portion 50 coupled to the radial movement is limited to 60 is also pivoted with the base portion (60).

On the other hand, the back pressure chamber 62 partitioned by the seal 62a is formed in the center of the upper surface of the base flange 64. Referring to FIG. 4, the back pressure chamber 62 is positioned between the bottom surface of the wrap flange 54 and the top surface of the base flange 64 and is inserted into and fixed to the base flange 64. The inner space of the back pressure chamber 62 is blocked from the low pressure space 11. The back pressure hole 54a communicates between the inner space of the back pressure chamber 62 and the compression chamber. It is formed through the flange 64.

Therefore, a portion of the compressed refrigerant present in the compression chamber is introduced into the back pressure chamber through the back pressure hole 54a in the process of sucking and compressing the refrigerant. Since the internal pressure of the back pressure chamber is higher than the pressure around the base flange 64, the base portion 60 rises along the axial direction from the wrap portion 50, through which the bottom of the fixed scroll and the pivot Sealing is made between the wraps 52.

Here, the pressure inside the back pressure chamber may be determined according to the position of the back pressure hole. That is, the pressure inside the back pressure chamber increases as the back pressure hole moves closer to the center of the swing wrap 52 of the swing scroll, and the pressure inside the back pressure chamber decreases as it moves outside.

5A to 5C are plan views schematically illustrating a process of compressing the refrigerant by the turning wrap and the fixed wrap, and the solid line corresponds to the center line of the fixed wrap 42 and the dotted line corresponds to the center line of the swing wrap 52, respectively. . 5C corresponds to the case where the pressure in the compression chamber reaches the discharge pressure and discharge starts. As described above, due to the operation principle of the scroll compressor, the pressure in the compression chamber formed by the swing wrap and the fixed wrap is continuously changed in the compression process. Thus, the pressure at any point of the turning wrap also changes continuously in one compression cycle.

For example, when the back pressure hole is at the point a, the point a is at a position maintained at the discharge pressure during the compression process, so that the same pressure as the discharge pressure is applied to the back pressure chamber. In this case, due to excessive back pressure, the thrust force between the bottom of the fixed scroll and the turning wrap is high, so the loss due to friction is increased. In addition, since the discharge pressure varies depending on the amount of compression load applied to the compressor, when the back pressure hole is formed at a point where the discharge pressure is continuously applied, such as point a, the thrust force varies depending on the load. Will affect performance. Specifically, the point a corresponds to a range within the discharge start time.

On the other hand, point b is a point at which the discharge pressure is applied for a predetermined time in the compression process, and the intermediate pressure between the suction pressure and the discharge pressure is applied at other times. Therefore, when the back pressure hole is applied to the point b, not only an appropriate back pressure can be secured, but also when the discharge pressure changes due to the load variation, etc., the buffer pressure is somewhat buffered due to the intermediate pressure. It can be offset to some extent. As a result of the present inventors, it was confirmed that the point b falls within a range of 180 degrees of the involute phase difference from the discharge start time of the turning wrap.

In the case of the point c, only the intermediate pressure is continuously applied during the compression process. When the back pressure hole is formed at the point c, the back pressure is too low to obtain a sufficient amount of sealing, which may cause refrigerant leakage. Is high.

FIG. 6 is a graph showing thrust forces generated under low load, overload, high differential pressure and high pressure ratio conditions when the back pressure holes are located at points a and b, respectively. Referring to FIG. 6, it can be seen that when the back pressure hole is located at a, not only the thrust force is excessively generated under the low load condition but also the deviation of the thrust force is large in each case. On the other hand, when the back pressure hole is located at b, relatively low thrust force is generated under low load conditions, and in each case, it can be seen that the variation in thrust force is relatively small.

On the other hand, unlike the first embodiment, an example in which the old dam ring is coupled to the fixed scroll (4) can also be considered. This case is shown in FIG. 7 is a cross-sectional view showing a second embodiment of the scroll compressor according to the present invention. Referring to FIG. 7, the old dam ring 6 is formed of the wrap portion 50 of the swing scroll, specifically, the wrap flange 54. It is installed on the upper surface. To this end, a first protrusion groove 4a for inserting the first protrusion 6b of the old dam ring 6 is formed at the bottom of the fixed scroll 4, through which the old dam ring 6 is formed. It is fixed so as not to rotate relative to the fixed scroll.

Here, the second protrusion (not shown) of the old dam ring 6 is inserted into the second protrusion groove (not shown) formed in the wrap flange 54.

Claims (14)

case;
A fixed scroll installed in the case;
A wrap part engaged with the fixed scroll to form a compression chamber;
A base portion to move the wrap portion to the fixed scroll side;
A driving motor coupled to a rear surface of the base part to eccentrically rotate the base part and the wrap part; And
And a main frame supporting the base part and installed in the case.
And a back pressure chamber communicating with the compression chamber between the wrap portion and the base portion. The method of claim 1,
The base portion
A boss coupled to the rotating shaft of the drive motor; And
A base flange facing the wrap portion;
And the back pressure chamber is formed on the base flange. The method of claim 2,
And a sealing means interposed between the base flange and the wrap portion to seal the back pressure chamber. The method of claim 1,
The wrap section
A wrap flange facing the base portion; And
Includes; the turning wrap engaging the fixed wrap of the fixed scroll,
And a back pressure hole communicating with the back pressure chamber and the compression chamber is formed through the wrap flange. The method of claim 4, wherein
And the back pressure hole is formed at a position to apply all of the discharge pressure and the intermediate pressure defined by the value between the discharge pressure and the suction pressure to the back pressure chamber. The method of claim 5,
And the back pressure hole is located at a point having a phase angle larger than α and smaller than α + 180 ° on the swing wrap when the discharge start time of the swing wrap is α. The method of claim 1,
And the wrap portion and the base portion are key coupled. The method of claim 7, wherein
The key is integrally formed on any one side of the wrap portion and the base portion, the scroll compressor, characterized in that a key hole coupled to the key is formed on the other side. The method of claim 1,
And the case is divided into two spaces having different pressures, and the wrap part and the base part are disposed in a space having a relatively low pressure among the two spaces. 10. The method of claim 9,
The case is a scroll compressor, characterized in that partitioned into two spaces having different pressures by the fixed scroll. Fixed scroll;
A swing scroll including a swing wrap for forming a compression chamber together with the fixed scroll, and coupling means for movably supporting the swing wrap toward the fixed scroll; And
And pressurizing means positioned on a rear surface of the swing wrap to generate a back pressure for introducing a portion of the working fluid of the compression chamber to move the swing wrap to a fixed scroll side. The method of claim 11,
Wherein the pressing means comprises:
Located on the back of the swing wrap, and includes a back pressure chamber having a pressure higher than the pressure on the outer peripheral side of the swing wrap,
And the back pressure chamber and the compression chamber communicate with each other. The method of claim 12,
And a back pressure hole communicating with the back pressure chamber and the compression chamber is formed in the swing scroll. The method of claim 13,
And the back pressure hole is formed at a position to apply all of the discharge pressure and the intermediate pressure defined by the value between the discharge pressure and the suction pressure to the back pressure chamber.

Images