KR101727498B1 - Scroll compressor with split type orbitting scroll - Google Patents

Abstract

The present invention relates to a scroll compressor having a separable orbiting scroll. According to an aspect of the present invention, there is provided a scroll compressor including a case; A fixed scroll installed in the case; A lap portion engaging with the fixed scroll to form a compression chamber; A base portion movably supporting the wrap portion to the fixed scroll side; A driving motor coupled to a back surface of the base portion to eccentrically rotate the base portion and the wrap portion; And a main frame installed in the case, the scroll compressor including a back pressure chamber communicating with the compression chamber is provided between the lap portion and the base portion.

Description

[0001] SCROLL COMPRESSOR WITH SPLIT TYPE ORBITTING SCROLL [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scroll compressor having a separable orbiting scroll, and more particularly, to a scroll compressor in which compression is performed while orbiting scroll is rotated with respect to a fixed scroll.

Generally, a scroll compressor is a compressor that compresses a refrigerant gas by changing a volume of a compression chamber formed by a pair of opposing scrolls. The scroll compressor is more efficient than a reciprocating compressor or a rotary compressor, has low vibration and noise, can be made compact and lightweight, and is widely used particularly in air conditioners.

The scroll compressor may be divided 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 is discharged to the inner space of the casing, so that the entire inner space of the casing is formed as the discharge space.

The scroll compressor may be divided into a tip chamber type and a back pressure type by a sealing method of a compression chamber. That is, in the tip chamber type, a tip chamber is provided at the tip of the lap of each scroll, so that the tip chamber of the compressor rises while the compressor is in operation, and is brought into close contact with the end plate of the opposite scroll. On the other hand, in the back pressure system, a back pressure chamber is formed on the back surface of one scroll, and oil or refrigerant of intermediate pressure is introduced into the back pressure chamber so that the scroll is pressed against the pressure of the back pressure chamber, Typically, the tip chamber 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 rotary shaft of the drive motor is coupled to one side of the orbiting scroll, and the other side of the orbiting scroll is engaged with the fixed scroll. Particularly, in the case of orbiting scroll, since both side surfaces rotate in contact with the fixed scroll and the main frame, it is necessary to precisely shape the shape in order to suppress the vibration and minimize the loss due to friction. For this purpose, the orbiting scroll is formed by machining the bearing surface to be in contact with the main frame and then machining the lap portion. However, there is a possibility that the bearing surface is damaged in the process of machining the lap portion. In addition, since the shape of the orbiting scroll and the fixed scroll, especially the shape and size of the wrap portion, must be different depending on the capacity of the compressor, a considerable time is required for designing and manufacturing the orbiting scroll.

The pressure applied to the back pressure chamber by the bearing surface of the orbiting scroll varies depending on the pressure applied to the back pressure chamber. In order to prevent the leakage of the refrigerant, the pressure applied to the back pressure chamber is properly maintained do. However, in the conventional scroll compressor, since the entire orbiting scroll must be supported by the pressure of the back pressure chamber, a considerable high pressure must be applied to the back pressure chamber, and if there is a variation in the back pressure chamber pressure, There is a problem that greatly affects the performance of the system. Particularly, 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 between the orbiting scroll and the fixed scroll and the friction loss are affected by the load fluctuation There was a problem.

It is a technical object of the present invention to provide a scroll compressor capable of achieving sufficient sealing performance while minimizing friction loss between orbiting scroll and fixed scroll even in the presence of load fluctuations.

According to an aspect of the present invention, A fixed scroll installed in the case; A lap portion engaging with the fixed scroll to form a compression chamber; A base portion movably supporting the wrap portion to the fixed scroll side; A driving motor coupled to a back surface of the base portion to eccentrically rotate the base portion and the wrap portion; And a main frame installed in the case, the scroll compressor including a back pressure chamber communicating with the compression chamber is provided between the lap portion and the base portion.

In the above aspect of the present invention, the orbiting scroll is configured to be divided into a base portion and a lap portion so that the lap portion and the base portion can be separately manufactured. This makes it possible to share the base portion in a plurality of compressors having different capacities, thereby making it easier to manufacture the orbiting scroll. A back pressure chamber is formed between the lap portion and the base portion so that only the lap portion, which is not the entire orbiting scroll, is brought into close contact with the fixed scroll side. Thus, even when the back pressure is relatively small, So that leakage can be prevented.

Here, the base portion may include a boss portion coupled to a rotation axis of the driving motor; And a base flange opposed to the lap portion, and the back pressure chamber may be formed in the base flange.

Between the base flange and the lap portion, a sealing means for sealing the back pressure chamber may be interposed.

The wrap portion may include a wrap flange facing the base portion; And a revolving lap engaged with the fixed lap of the fixed scroll. A back pressure hole communicating the back pressure chamber and the compression chamber may be formed through the lap flange. Accordingly, since the length of the back pressure hole can be shortened, the loss of the back pressure can be minimized, and the back pressure hole can be easily processed.

The back pressure hole may be formed at a position where 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. The pressure applied to the compression chamber continuously varies depending on the operation principle of the scroll compressor. Specifically, at the outermost of the fixed lap and the orbiting lap, the pressure corresponding to the suction pressure gradually increases to have an intermediate pressure, Discharge occurs while reaching the pressure. Further, since the pressure chamber has a shape extending in the circumferential direction similar to the crescent moon, the pressure at a specific position of the orbiting scroll also changes.

Depending on the position, both the intermediate pressure and the discharge pressure can be applied. When the back pressure hole is formed at this position, the intermediate pressure is applied to the back pressure chamber at the beginning, and the discharge pressure is also applied while the orbiting wrap is rotated. Therefore, pressure to be interlocked with the compression chamber is applied to the back pressure chamber. In other words, when the pressure in the compression chamber is low, it is advantageous to reduce the loss due to friction by lowering the discharge pressure because there is less fear of leakage relatively. When the pressure in the compression chamber is high, It is necessary to shut off the leakage. By the above-described configuration, it becomes possible to appropriately adjust the discharge pressure.

Specifically, when the discharge opening time of the orbiting wrap is?, The back pressure hole may be located at a point having a phase angle larger than? And smaller than? + 180 ° on the orbiting wrap.

The lap portion and the base portion may be keyed, and a key may be integrally formed on one of the lap portion and the base portion, and a keyhole formed on the other side may be formed.

On the other hand, the case is divided into two spaces having different pressures, and the lap and base portions can be disposed in a space having a relatively low pressure among the two spaces. In this case, the case may be divided into two spaces having different pressures by the fixed scroll.

According to another aspect of the present invention, there is provided a scroll compressor including: a fixed scroll; A orbiting scroll forming a compression chamber together with the fixed scroll, and a coupling means for movably supporting the orbiting wrap to the fixed scroll side; And a pressurizing means located on the back surface of the orbiting wrap for generating a back pressure for introducing a part of the working fluid of the compression chamber and moving the orbiting wrap to the fixed scroll side.

Here, the pressing means includes a back pressure chamber which is located on the back surface of the orbiting wrap and has a pressure higher than that of the outer circumferential side of the orbiting wrap, and the back pressure chamber and the compression chamber can communicate with each other.

Further, a back pressure hole for communicating the back pressure chamber and the compression chamber may be formed in the orbiting scroll.

According to aspects of the present invention having the above-described structure, by separating the orbiting scroll into two parts, a sufficient degree of sealing can be achieved even at a relatively low back pressure, A pressure lower than the discharge pressure can be used as the discharge pressure, so that the compressor can be driven more stably.

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

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

1 to 3, the scroll compressor according to the present invention is characterized in that the inner space of the case 1 is divided into a suction space 11 as a low pressure portion and a discharge space 12 as a high pressure portion, And a main frame 3 is fixedly installed between the suction space 11 and the discharge space 12 of the case 1. The main frame 3 is fixed to the suction space 11 of the case 1, A fixed scroll 4 is fixed to an upper surface of the main frame 3 and is eccentrically coupled to a crankshaft 23 of the driving motor 2 between the main frame 3 and the fixed scroll 4, An orbiting scroll (5) forming a pair of two compression chambers (P) continuously moving together with the fixed scroll (4) is pivotally mounted. An ore ring 6 is provided between the fixed scroll 4 and the orbiting scroll 5 to prevent the orbiting scroll 5 from rotating.

The suction pipe 13 is connected to the suction space 11 of the case 1 while the discharge pipe 14 is connected to the discharge space 12. [

Here, although not shown in the drawing, the casing may be provided with a sealed predetermined discharge space and partitioned by a discharge plenum fixedly coupled to the fixed scroll 4, the suction space being a low pressure part and the discharge space being a high pressure part, The inner space of the case may be partitioned into a suction space and a discharge space by a high-low pressure separation plate (not shown) fixed to the upper surface of the fixed scroll and closely attached to the inner circumferential surface of the case.

The stationary scroll 4 protrudes from the bottom surface of the fixed plate 41 and is formed in an involute shape so as to form a compression chamber P together with the orbiting wrap 52 of the orbiting scroll 5 . A suction port (not shown) is formed on the outer peripheral surface of the fixed plate 4 of the fixed scroll 4 so that the suction space 11 of the case 1 communicates with the compression chamber P, A discharge port 44 is formed at the center of the hard plate portion 41 so that the compression chamber P and the discharge space 12 of the case 1 communicate with each other. In the drawings, reference numeral 7 denotes a sub-frame, 8 denotes a discharge valve, 21 denotes a stator, and 22 denotes 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 flows into the suction port And is compressed and moved to the center of the orbiting scroll and the fixed scroll by the orbiting scroll 5 and then discharged to the discharge space 12 of the case 1 through the discharge port 44 of the fixed scroll 4 The process of discharging is repeated.

2 and 3, the orbiting scroll 5 is configured to be divided into two parts. Specifically, the orbiting scroll 5 and the lap portion 50, which are engaged with the fixed scroll, (Not shown). The lap portion 50 is configured to include a revolving lap 52 that engages with the fixed lap 42 to form a compression chamber and a lap flange 54 integrally formed with the revolving lap 52. The lap flange 54 has a disk shape, and on both sides of the bottom surface, a key portion 56 for engaging with the base portion 60 is formed.

The base portion 60 is coupled to the lap 50 in a state of being opposed to the bottom surface of the lap flange 54. Specifically, the base portion 60 includes a base flange 64, And a boss portion 68 formed on the bottom surface of the base flange 64 to engage with the crankshaft 23 described above.

A keyhole 66 for fastening with the key-shaped portion 56 is formed at both side edges of the upper surface of the base flange 64. By inserting the key-shaped portion into the keyhole, the lap 50 can move in the axial direction of the crankshaft with respect to the base portion 60, but can not be moved with respect to the radial direction or the circumferential direction of the base portion do. However, since the axial movement of the lap 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 . That is, both of them can be stably combined by simply inserting the key portion into the keyhole without using a method such as bolt fastening or welding.

In addition, the above-mentioned anti-blocking 6 as the above-described anti-rotation mechanism is coupled to the bottom surface of the base portion 60. Specifically, the alum ring 6 includes a ring-shaped portion 6a contacting with the bottom surface of the base flange 64, and two opposite sides of the ring-shaped portion 6a are provided with two First protrusions 6b are formed. The first protrusion 6b is inserted into the first protrusion groove 3a formed in the main frame 3. Two second protrusions 6c are also formed on both sides of the upper surface of the ring-shaped portion 6b with a phase difference of 180 degrees. The second protrusions 6c are inserted into second protrusion grooves 64a formed on the bottom surface of the base flange 64, respectively.

Accordingly, even if the crankshaft 23 transmits rotational force to the base portion 60, the base portion 60 is pivotally moved in a state where the base portion 60 is prevented from being rotated by the otal bearing 6, The lap portion 50 coupled to limit the radial movement of the lap portion 60 is also pivoted together with the base portion 60.

On the other hand, a back pressure chamber 62 is defined at the center of the upper surface of the base flange 64 by a seal 62a. 4, the back pressure chamber 62 is positioned between the bottom surface of the lap flange 54 and the upper surface of the base flange 64, and a seal 62a Pressure space 62 communicates with the internal space of the back pressure chamber 62. The back pressure chamber 62 communicates with the compression chamber 62 through the back pressure chamber 62, Is formed through the flange (64).

Therefore, in the process of sucking and compressing the refrigerant, a part of the compressed refrigerant present in the compression chamber flows into the back pressure chamber through the back pressure hole 54a. Since the internal pressure of the back pressure chamber becomes higher than the pressure around the base flange 64, the base portion 60 is lifted along the axial direction from the lap portion 50, The sealing is performed between the wraps 52.

Here, the pressure in 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 orbiting wrap (52) of the orbiting scroll, and the pressure inside the back pressure chamber decreases as it moves outward.

5A to 5C are plan views schematically showing a process in which the refrigerant is compressed by the orbiting wrap and the fixed lap. The solid line corresponds to the center line of the fixed lap 42, and the dotted line corresponds to the center line of the orbiting wrap 52 . Fig. 5C corresponds to the case where the pressure in the compression chamber reaches the discharge pressure and discharge starts. As described above, on the operating principle of the scroll compressor, the pressure in the compression chamber formed by the orbiting wrap and the fixed wrap continuously changes during the compression process. Thus, the pressure at any point in the orbiting wrap also changes continuously within one compression cycle.

For example, when the back pressure hole is located at the point a, the point a is held at the discharge pressure in 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 surface of the fixed scroll and the orbiting wrap is high, so that the loss due to friction becomes large. Since the thrust force varies depending on the load when the discharge pressure is varied depending on the compression load applied to the compressor, when the back pressure hole is formed at the point where the discharge pressure is continuously applied as in the point a, The performance of the system will be affected. Specifically, the point a corresponds to a range within the ejection opening time.

On the other hand, the point b is a point at which the discharge pressure is applied for a predetermined time during 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 double pressure can be ensured, but even when the discharge pressure changes due to the load variation or the like, the influence due to the load fluctuation Can be offset to some extent. As a result of research conducted by the present inventor, it has been confirmed that the point b corresponds to a range within 180 degrees of the intellectual retardation from the discharge opening time of the orbiting wrap.

In the case of the point c, in the case of forming the back pressure hole at the point c at which only the intermediate pressure is continuously applied during the compression process, it is difficult to obtain a sufficient degree of sealing because the back pressure is too low, 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 positions a and b, respectively. Referring to FIG. 6, it can be seen that the thrust force is excessively generated at the low load condition when the back pressure hole is located at a, and the thrust force deviation is large in each case. On the other hand, when the back-pressure hole is located at b, relatively low thrust force is generated at low load condition, and the variation of thrust force is relatively small in each case.

On the other hand, unlike the first embodiment, an example in which the abovementioned sealing is coupled to the fixed scroll 4 is also contemplated. Such a 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 above-mentioned bearing 6 is mounted on the wrap portion 50 of the orbiting scroll, And is installed on the upper surface. A first protrusion groove 4a for inserting the first protrusion 6b of the oralling ring 6 is formed on the bottom surface of the fixed scroll 4, And is fixed not to rotate with respect to the fixed scroll.

Here, a second protrusion (not shown) of the above-mentioned sealing ring 6 is inserted into a second protrusion groove (not shown) formed in the lap flange 54.

Claims (14)

case;
A fixed scroll installed in the case;
A lap portion having a lap flange formed integrally with the orbiting lap at a lower portion and formed in a disc shape;
A base portion movably supporting the wrap portion to the fixed scroll side;
A driving motor coupled to a back surface of the base portion to eccentrically rotate the base portion and the wrap portion; And
And a main frame supporting the base portion and installed in the case,
A back pressure chamber is formed between the lap portion and the base portion,
The back pressure chamber is communicated with the compression chamber by a back pressure hole formed to pass through the lap flange,
The back pressure hole is formed such that when the discharge opening time of the orbiting wrap is?, The back pressure hole is formed on the orbiting wrap so as to be larger than? On the orbiting wrap so that the discharge pressure and the intermediate pressure defined as a value between the discharge pressure and the suction pressure are applied to the back pressure chamber, And is located at a point having a phase angle smaller than? + 180 °. The method according to claim 1,
The base portion
A boss unit coupled to a rotation axis of the driving motor; And
And a base flange opposed to the lap portion,
And the back pressure chamber is formed in the base flange. 3. The method of claim 2,
And a sealing means for sealing the back pressure chamber is interposed between the base flange and the lap portion. delete delete delete The method according to claim 1,
Wherein the lap portion and the base portion are key-engaged. 8. The method of claim 7,
Wherein a key is integrally formed at one side of the lap portion and the base portion, and a keyhole is formed at the other side of the key portion to be coupled with the key. The method according to claim 1,
Wherein the case is divided into two spaces having different pressures, and the lap portion and the base portion are disposed in a space having a relatively low pressure among the two spaces. 10. The method of claim 9,
Wherein the case is divided into two spaces having different pressures by the fixed scroll. Fixed scroll;
A orbiting scroll forming a compression chamber together with the fixed scroll, and a coupling means for movably supporting the orbiting wrap to the fixed scroll side; And
And a pressing means which is located on the back surface of the orbiting wrap and generates a back pressure for introducing a part of the working fluid of the compression chamber to move the orbiting wrap to the fixed scroll side,
Wherein the pressing means includes a back pressure chamber which is located on the back surface of the orbiting wrap and has a pressure higher than that of the outer circumferential side of the orbiting wrap,
The back pressure chamber communicates with the compression chamber by a back pressure hole formed in the orbiting scroll,
The back pressure hole is formed such that when the discharge opening time of the orbiting wrap is?, The pressure in the back pressure chamber is set to be? (?) On the orbiting wrap so that the back pressure chamber is applied with a discharge pressure and an intermediate pressure defined as a value between the discharge pressure and the suction pressure, And is located at a point having a phase angle smaller than? + 180 °. delete delete delete

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