WO2006019010A1

WO2006019010A1 - Scroll compressor

Info

Publication number: WO2006019010A1
Application number: PCT/JP2005/014557
Authority: WO
Inventors: Akira Hiwata; Takashi Morimoto; Yoshiyuki Futagami; Tsutomu Tsujimoto
Original assignee: Matsushita Electric Industrial Co., Ltd.
Priority date: 2004-08-17
Filing date: 2005-08-09
Publication date: 2006-02-23
Also published as: JP2007315172A

Abstract

A scroll compressor capable of reducing a re-expansion loss by reverse flow while reducing a delivery pressure loss, wherein each of winding start portions of the volute wraps of a fixed scroll (12) and a turning scroll (13) is formed of a first outer circular arc smoothly connecting the tip of the volute wrap to the winding start point (B) of an outer wall involute curve and a second inner circular arc in smooth contact with the winding start point (A) of an inner wall involute curve. In the fixed scroll (12), the first outer circular arc and the second inner circular arc are formed by connecting them to each other with a third inner circular arc not smoothly connected to these circular arcs. Thus, even if operating conditions are changed, a high efficiency can be realized by preventing the reverse flow from a delivery space despite the fact that the resistance of a delivery gas passage at the end of compression is reduced.

Description

Scroll compressor

Technical field

[0001] The present invention provides a compression chamber formed between a fixed scroll and an orbiting scroll so that the compression chamber has a volume when the orbiting scroll is turned under the restriction of rotation by the rotation restriction mechanism. The present invention relates to a scroll compressor that sucks, compresses, and discharges working fluid by moving while changing. Background art

Conventionally, in this type of scroll compressor, the spiral winding wrap of each scroll has a winding start portion, an outer circular arc in which the wrap tip smoothly connects with the winding start point of the outer wall involute curve, and winding of the inner wall involute curve. It consists of two arcs of the starting point and the inner arc smoothly connected, or the winding start part of each scroll's spiral wrap and the outer arc whose lap tip is smoothly connected to the winding start point of the outer wall involute curve In some cases, the inner wall involute curve is composed of two arcs of a winding start point and an inner arc that is not smoothly connected (for example, see Patent Document 1).

That is, the scroll compressor has two compression chambers as shown in FIGS. 4 and 5, and the first compression formed by the inner wall surface 26d of the rotating scroll wrap 26b and the outer wall surface 24c of the fixed scroll wrap 24b. Chamber 25a and two compression chambers formed by outer wall surface 26e of orbiting scroll wrap 26b and inner wall surface 24d of fixed scroll wrap 24b. Both compression chambers 25a and 25b are scrolled. The gas in the compression chamber is compressed and discharged from the discharge hole 21 by performing relative motion of both scrolls so as to reduce the volume as it moves in the center direction.

Since the second compression chamber 25b reaches the design volume ratio (suction volume Z discharge volume) and then communicates with the discharge hole 21 (arrow X in FIG. 5), a sufficient discharge passage can be secured. On the other hand, the first compression chamber 25a communicates with the discharge hole 21 through the passage between the inner wall surface 26d of the orbiting scroll wrap 26b and the outer wall surface 24c of the fixed scroll wrap 24b (arrow Y in FIG. 5). Not. However, when the compressed gas flows to the discharge chamber, it passes between the wall surfaces of the scroll wrap. iS If the distance between the laps is narrow, the resistance of the discharge gas passage (hereinafter referred to as discharge resistance) increases, which increases the compressor input and lowers the efficiency.

Therefore, in order to solve the above problem, as shown in FIG. 6, the winding start portion of the fixed scroll wrap 24b is connected to the outer arc 24e in which the wrap tip smoothly connects to the winding start point B of the outer involute curve, and the inner involute Consists of two arcs, the inner arc 2 4f, which is not smoothly connected to the winding start point A, widens the gas passage immediately after discharge, reduces the increase in compressor input due to discharge resistance, and improves compression efficiency A scroll compressor with a configuration that allows this is proposed.

Patent Document 1: JP 2000-120565 A

Disclosure of the invention

Problems to be solved by the invention

[0003] However, in the conventional scroll compressor, when the diameter of the inner arc is changed in order to reduce the discharge resistance, the passage condition suddenly widens immediately after the end of compression, so that the operating conditions change. When the volume ratio is a little larger than the design volume ratio, there was a problem that a back flow from the discharge space occurred and the compressor input increased.

[0004] Accordingly, the present invention solves the conventional problems, and provides a scroll compressor that achieves high efficiency by preventing back flow from the discharge space while reducing discharge resistance at the end of compression. It is aimed.

Means for solving the problem

[0005] The scroll compressor according to the first aspect of the present invention is configured such that a compression scroll is formed between both the fixed scroll and the orbiting scroll where the spiral wrap rises with the end plate force, and the orbiting scroll is rotated by a rotation restricting mechanism. In the scroll compressor that sucks, compresses, and discharges the working fluid by moving the compression chamber while changing the volume when swung under the regulation of A first outer arc that smoothly connects the portion to the outer wall winding start point of the outer wall involute curve, a second inner arc that smoothly connects the inner wall winding start point of the inner wall involute curve, and the first outer arc A third inner arc that is connected to the arc and the second inner arc at discontinuous points, respectively, and a radius R3 that forms the third inner arc is a radius that forms the second inner arc. R2 Also small It is characterized by that.

According to a second aspect of the present invention, in the first aspect, the outer wall of the swirl wrap of the orbiting scroll The inner wall involute curve of the swirl wrap of the fixed scroll extended to near the end of winding of the involute curve. It is characterized by the formation of an inner wall.

According to a third aspect of the present invention, in the first aspect, the wall surface of the third inner arc is formed as a part of the discharge port.

According to a fourth aspect of the present invention, in the first aspect of the invention, the distance between the second inner arc and the outer wall involute curve is increased with respect to the wrap thickness of the fixed scroll. According to a fifth aspect of the present invention, in the first aspect, the refrigerant as the working fluid is carbon dioxide.

The invention's effect

[0006] The scroll compressor according to the present invention achieves high efficiency by preventing back flow from the discharge space while reducing discharge resistance at the end of compression. In particular, high efficiency can be achieved when a diacid carbonate refrigerant, which is a high pressure and low compression ratio refrigerant, is used.

Brief Description of Drawings

[0007] FIG. 1 is a sectional view of a scroll compressor in an embodiment of the present invention.

FIG. 2 is an enlarged plan view of the main part of the winding start portion of the fixed scroll wrap in the scroll compressor of this embodiment.

FIG. 3 is a main part plan view showing a discharge process state in the scroll compressor of the present embodiment. FIG. 4 is a main part plan view showing a compression chamber in a conventional scroll compressor.

[Figure 5] Enlarged plan view of the main part of the wrap center in a conventional scroll compressor

FIG. 6 is an enlarged plan view of the main part of the lap center in another conventional scroll compressor.

[0008] 4 crankshaft

4a Main shaft

11 Main bearing member

12 Fixed scroll 13 Rotating scronore

14 Rotation regulation mechanism

15 Compression chamber

121 First outer arc

122 Second inner arc

123 3rd inner arc

A Inner wall winding start point

B Outside wall winding start point

C First discontinuity

D second discontinuity

BEST MODE FOR CARRYING OUT THE INVENTION

The scroll compressor according to the first embodiment of the present invention includes a first outer arc that smoothly connects a winding start portion of a spiral scroll of a fixed scroll to an outer wall winding start point of an outer wall involute curve, and an inner wall The second inner arc is smoothly connected to the inner wall winding start point of the involute curve, and the third inner arc is connected to the first outer arc and the second inner arc at discontinuous points. The radius R3 that forms the third inner arc is made smaller than the radius R2 that forms the second inner arc. According to the present embodiment, immediately after the end of compression, the minimum distance between the outer wall of the orbiting scroll and the inner wall of the fixed scroll increases smoothly, so that the third inner arc is reached while preventing backflow from the discharge space. In this case, since the discharge passage can be increased rapidly, the backflow loss can be reduced and the discharge resistance can be reduced. As a result, high efficiency can be realized in operation at the design volume ratio. Even if the operating conditions change and the volume ratio becomes a little larger than the design volume ratio, the discharge passage increases smoothly and gradually, so the increase in compressor input can be suppressed. A highly efficient scroll compressor can be provided over an area. The second embodiment of the present invention is the scroll compressor according to the first embodiment, wherein the inner wall involute curve of the swirl wrap of the fixed scroll extended to the vicinity of the winding end of the outer wall involute curve of the swirl scroll of the orbiting scroll. Thus, the inner wall of the fixed scroll spiral wrap is formed. According to this embodiment, the discharge passage Even when the path becomes long and pressure loss becomes a problem, the backflow loss is small and the discharge resistance can be reduced, so that a more efficient scroll compressor can be provided.

The third embodiment of the present invention is such that the wall surface of the third inner arc is formed as a part of the discharge port in the scroll compressor according to the first embodiment. According to the present embodiment, immediately after the end of compression, the minimum distance between the outer wall of the orbiting scroll and the inner wall of the fixed scroll increases smoothly, so that the third inner arc is reached while preventing backflow from the discharge space. In this case, since the discharge passage can be increased suddenly and directly discharged, the discharge resistance can be reduced, and a more efficient scroll compressor can be provided. In the scroll compressor according to the first embodiment, the fourth embodiment of the present invention is such that the distance between the second inner arc and the outer wall involute curve is increased with respect to the wrap thickness of the fixed scroll. is there. According to the present embodiment, during high load operation, the strength near the tip of the lap can be increased to suppress deformation of the end plate of the fixed scroll, and abnormal wear can be prevented. In addition, since the space that has reached the discharge pressure immediately after the end of compression can be reduced, the refrigerant that re-expands into the compression chamber and backflows can be reduced, thus providing a more efficient scroll compressor. can do.

According to a fifth embodiment of the present invention, in the scroll compressor according to the first embodiment, the refrigerant as the working fluid is diacid carbon. According to the present embodiment, in the case of carbon dioxide and carbon dioxide, the density is about 3 to 4 times higher than that of the HFC refrigerant, so by reducing the refrigerant that re-expands into the compression chamber and flows backward, A more efficient crawl compressor can be provided.

Example

Embodiments of the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the embodiments.

FIG. 1 shows a cross-sectional view of a scroll compressor according to an embodiment of the present invention.

In the scroll compressor of this embodiment shown in FIG. 1, a main bearing member 11 that supports a crankshaft 4 is fixed in a sealed container 1 by welding or shrink fitting. A fixed scroll 12 is bolted on the main bearing member 11. Between main bearing member 11 and fixed scroll 12 The orbiting scroll 13 is held between the fixed scroll 12 and the fixed scroll 12. Each of the fixed scroll 12 and the orbiting scroll 13 is configured by raising the spiral wrap with the end plate force. Between the orbiting scroll 13 and the main bearing member 11, a rotation restricting mechanism 14 such as an Oldham ring for preventing the orbiting scroll 13 from rotating and guiding it to move in a circular orbit is provided. The main shaft portion 4a at the upper end of the crankshaft 4 drives the orbiting scroll 13 eccentrically. As a result, the volume of the compression chamber 15 formed between the fixed scroll 12 and the orbiting scroll 13 is reduced while moving from the outer peripheral side to the central portion. Refrigerant gas sucked from the suction pipe 16 communicating with the outside of the hermetic container 1 is introduced into the compression chamber 15 from the suction port 17 in the outer peripheral portion of the fixed scroll 12 and is compressed in the compression chamber 15. Then, the refrigerant gas having a pressure equal to or higher than a predetermined pressure pushes the lead valve 19 through the discharge port 18 provided at the center of the fixed scroll 12 to be discharged into the discharge space in the sealed container 1.

FIG. 2 is an enlarged plan view of a main part of a winding start portion of the fixed scroll wrap in the scroll compressor of this embodiment.

As shown in FIG. 2, the winding start portion of the spiral wrap of the fixed scroll 12 in this embodiment is the inner wall winding start point A force and the outer wall winding start point B. The inner wall of the fixed scroll 12 has an inner wall involute curve, and the outer wall winding start point B of the fixed scroll 12 has an inward curve. It is configured. The winding start portion of the spiral wrap of the fixed scroll 12 has a first discontinuity point C formed on the inner wall winding start point A side and a second discontinuity point D formed on the outer wall winding start point B side. is doing. And between the outer wall winding start point B and the second discontinuous point D is formed by the first outer arc 121 of radius R1, and the inner wall winding start point A force is also between the first discontinuous point C and , Formed by a second inner arc 122 of radius R2. Further, the first discontinuous point C force is formed by the third inner arc 123 having a radius R3 until the second discontinuous point D is reached. Here, the radius R 3 that forms the third inner arc 123 is smaller than the radius R 2 that forms the second inner arc 122. The radius R1 that forms the first outer arc 121 is smaller than the radius R3 that forms the third inner arc 123. In addition, the wavy line in the figure shows the case where the inner wall wrapping inner wall is formed by the inner wall involute curve from the inner wall winding start point A of the fixed scroll 12 to the inner periphery. The inner wall involute curve indicated by the wavy line and the second inner arc 122 The area surrounded by the third inner arc 123 is a dead volume reduction area. In the present embodiment, the compression chamber 15 is particularly reduced by the dead volume reduction area between the inner wall involute curve and the second inner arc 122. Sudden backflow to is suppressed.

The first outer arc 121 is smoothly connected to the outer wall involute curve at the outer wall winding start point B. The second inner arc 122 is smoothly connected to the inner wall involute curve at the inner wall winding start point A. Here, smooth connection means that the tangent slope is continuous.

On the other hand, the third inner arc 123 is connected to the first outer arc 121 at a discontinuity point D, and is connected to the second inner arc 122 at a discontinuity point C. That is, the third inner arc 123 and the first outer arc 121 are not smoothly connected, and the third inner arc 123 and the second outer arc 122 are not smoothly connected.

In the present embodiment, the wall surface of the third inner arc 123 is formed as a part of the discharge port 18. By forming the wall surface of the third inner circular arc 123 as a part of the discharge port 18, even if the diameter is increased in order to reduce the discharge resistance of the discharge port 18, it flows backward to the compression chamber 15. The volume can be reduced.

Also, by increasing the distance between the second inner arc 122 and the outer wall involute curve of the fixed scroll 12 with respect to the wrap thickness X of the fixed scroll 12, the strength near the tip of the lap can be increased during high load operation. It can be raised to suppress the deformation of the end plate of the fixed scroll 12 to prevent abnormal wear. In addition, since the space that has reached the discharge pressure immediately after the end of compression can be made smaller, the amount of refrigerant that re-expands into the compression chamber and backflows can be reduced, and a more efficient scroll compressor can be achieved. Can be provided.

FIG. 3 is a plan view of a principal part showing a state of a discharge process in the scroll compressor of the present embodiment. Figure (a) is 0 ° (or 360 °), Figure (b) is rotated 60 °, Figure (c) is rotated 120 °, Figure (d) is rotated 180 ° Figure (e) shows a state rotated by 240 °, and Figure (f) shows a state rotated by 300 °.

In FIG. 3, paying attention to the compression chamber 15 formed on the outer wall side of the orbiting scroll 13, the compression chamber 15 communicates with the discharge port 18 when the rotation angle is approximately 60 to 120 °. The discharge passage near the rotation angle of 120 ° is narrowed as shown in the figure while reducing the discharge resistance. However, the backflow from the discharge port 18 is moderately prevented. Further, it can be seen that the discharge passage portion is dramatically enlarged from when the orbiting scroll 13 reaches the third inner circular arc 123 (rotation angle 180 °). At this time, since the pressure in the compression chamber 15 is sufficiently high and there is no fear of backflow, the discharge resistance can be reduced.

[0014] By the way, regarding the relationship between the discharge pressure loss and the re-expansion loss due to the backflow, generally, in the configuration in which the discharge passage after the compression is enlarged, the discharge pressure loss can be reduced, but the re-expansion loss is large. On the contrary, in the configuration where the discharge passage is made small, the reexpansion loss (backflow loss) can be reduced. However, in the configuration of the present embodiment, the discharge passage can be expanded rapidly while suppressing the backflow, and at the same time, the dead volume of the discharge port 18 is reduced, so that the amount of refrigerant flowing back is also reduced. be able to. As a result, the discharge pressure loss and the backflow loss can be reduced. As can be seen from FIG. 3, it can be seen that the volume (dead volume) connected to the discharge port 18 is reduced as compared with the conventional wrap tip shape indicated by the broken line.

[0015] Even when the operating conditions change and the volume ratio becomes a little larger than the design volume ratio, the discharge passage increases smoothly and gradually, and backflow is suppressed to suppress an increase in compressor input. Therefore, according to this embodiment, a highly efficient scroll compressor can be provided over the entire operation range.

In addition, the scroll of scroll 13 is formed by forming the inner wall of the spiral wrap 12 of the fixed scroll 12 by the inner wall of the scroll 12 of the fixed scroll 12 that extends to the end of the winding end of the spiral scroll 12 of the spiral wrap. Even when the compression ratio of the compression chamber 15 formed on the outer wall side of the orbiting scroll 13 is larger than the compression ratio of the compression chamber 15 formed on the inner wall side of 13, the balance between the backflow loss and the discharge resistance is increased. Therefore, it is possible to provide a more efficient scroll compressor.

Note that the refrigerant as the working fluid is a high-pressure refrigerant, for example, carbon dioxide, and in the case of carbon dioxide, the density is about 3 to 4 times higher than that of the HFC-based refrigerant. Thus, the refrigerant that flows backward can be reduced. Therefore, if the configuration of this embodiment is used, a more efficient scroll compressor can be provided. Industrial applicability

As described above, the scroll compressor according to the present invention achieves high efficiency by reducing the discharge resistance at the end of compression and preventing the back flow of the discharge spatial force even when the operating conditions change. It can also be applied to scroll fluid machinery applications such as air scroll compressors and scroll type expanders that limit fluid to refrigerants.

Claims

The scope of the claims

[1] When the end plate force is squeezed between the fixed scroll and the orbiting scroll where the spiral wrap rises to form a compression chamber between them, and the orbiting scroll is rotated under the rotation restriction by the rotation restriction mechanism In the scroll compressor that sucks, compresses, and discharges the working fluid by moving the compression chamber while changing the volume, the winding start portion of the spiral scroll of the fixed scroll is set to the winding start point of the outer wall involute curve. The first outer arc connecting smoothly to the inner wall, the second inner arc connecting smoothly to the inner wall winding start point of the inner wall involute curve, and the first outer arc and the second inner arc are discontinuous. And a third inner arc connected at a point, and a radius R3 forming the third inner arc is made smaller than a radius R2 forming the second inner arc. Compressor.

[2] The inner wall of the swirl wrap of the fixed scroll is formed by the inner wall involute curve of the swirl wrap of the fixed scroll that extends to the end of the involute curve of the outer scroll of the swirl scroll. The scroll compressor according to claim 1.

[3] The scroll compressor according to claim 1, wherein a wall surface of the third inner arc is formed as a part of a discharge port.

4. The scroll compressor according to claim 1, wherein a distance between the second inner arc and the outer wall involute curve is increased with respect to a lap thickness of the fixed scroll.

5. The scroll compressor according to claim 1, wherein the refrigerant as the working fluid is carbon dioxide.