JP4745015B2 - Scroll compressor - Google Patents

Description

  The present invention relates to a scroll compressor which is a kind of positive displacement fluid machine, and particularly suitable for a scroll compressor for a refrigerator application product using a low-temperature refrigerant such as R404A, R507A, R508B, R410A or hydrocarbon as a working fluid. It is a thing.

  The set volume ratio of the scroll compressor is represented by the ratio between the stroke volume and the volume of the minimum sealed space. In operation (high pressure ratio operation) in which the discharge pressure is higher than the pressure in the minimum sealed space, the larger the set volume ratio, the smaller the input of the scroll compressor, and the better the scroll compressor's illustration efficiency.

  Therefore, in the scroll compressor described in Japanese Patent Application Laid-Open No. 7-27065 (Patent Document 1), it has been proposed to use an algebraic spiral for the basic vortex curve constituting the orbiting scroll wrap and the fixed scroll wrap. As a result, the volume change rate can be set, and the set volume ratio can be increased as compared with the case of designing with an involute of a circle, so that the performance can be improved by reducing the indicated power due to insufficient compression of the refrigerant.

  Further, in the scroll compressor described in Japanese Patent Laid-Open No. 10-89269 (Patent Document 2), the point corresponding to the wrap winding start angle of one scroll is delayed from the separation from the inner wall of the other scroll wrap. It is proposed that the gas in this space flows out to the discharge port through the sub-flow path. As a result, the set volume ratio can be increased, and the efficiency of illustration in the high pressure ratio operation can be improved.

JP 7-27065 A Japanese Patent Laid-Open No. 10-89269

  Patent Document 1 and Patent Document 2 described above disclose increasing the set volume ratio, but no consideration is given to the flow resistance loss when discharged from the discharge port. If the discharge port is simply made small in order to increase the set volume ratio, the flow path resistance loss of the discharge port may exceed the improvement in the illustrated efficiency, which may lead to a decrease in the compressor coefficient of performance (COP).

  Therefore, various studies were made on the flow resistance loss of the discharge port, and the ratio between the plane area of the minimum sealed space and the opening area of the discharge port when the compression chamber started to communicate with the discharge port greatly affects the coefficient of performance of the compressor. I understood that.

  Note that Patent Document 2 discloses that the discharge port shape is an ellipse, a polygon, or the like in order to increase the set volume ratio and configure the formation delay of the sub-flow channel of the discharge gas. Since machining is more complicated than when the outlet shape is circular, there is a problem that the machining cost is high particularly in a small scroll compressor.

An object of the present invention is to provide a scroll compressor capable of improving a compressor performance coefficient during a high pressure ratio operation in accordance with a relationship between an illustrated efficiency by a set volume ratio and a loss at a discharge port .

In order to achieve the above-mentioned object, the present invention has a turning scroll and a fixed scroll having a spiral wrap formed upright on an end plate, and the scrolls are directed toward each other. In combination, a sealed space is formed by the respective wraps and the end plate on the wrap outer wall surface side of the orbiting scroll and the wrap inner wall surface side of the fixed scroll, and as the two scrolls move relative to each other in the center direction, In the scroll compressor that reduces the volume of the sealed space and compresses the gas sucked from the outer peripheral sides of the scrolls and discharges the gas from the discharge port provided at the center of the scroll, the fixed scroll and the orbiting scroll are in a polar coordinate format. Algebraic spiral represented by the equation r = a · θk, where radius r, declination θ, algebraic spiral coefficient a, and algebraic spiral index k A spiral wrap using a curve and a stroke volume in the range of 5 to 25 cm ³ , and the planar area of the minimum sealed space and the opening area of the discharge port when the sealed space starts to communicate with the discharge port The ratio is in the range of 5.8 to 7.7 .

A more preferable specific configuration example of the present invention is as follows.
(1) as compressed to the working fluid R404A, R507A, R508B, R410A, for the use of any one of the low-temperature refrigerant of hydrocarbon.
( 2 ) The discharge port is enlarged so that the area on the discharge side is larger than the opening area to the sealed space.

ADVANTAGE OF THE INVENTION According to this invention, the scroll compressor which can improve the compressor performance coefficient at the time of high pressure ratio operation | movement by the relationship between the illustration efficiency by setting volume ratio and the loss in a discharge port can be provided.

Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. The same reference numerals in the drawings of the respective embodiments indicate the same or equivalent.
(First embodiment)
A scroll compressor according to a first embodiment of the present invention will be described with reference to FIGS.

  First, the overall configuration of the scroll compressor of the present embodiment will be described with reference to FIG. FIG. 1 is a longitudinal sectional view of a scroll compressor 50 of the present embodiment.

  The scroll compressor 50 of the present embodiment is an example of a horizontally installed scroll compressor for a refrigerator application product. The scroll compressor 50 uses a low-temperature refrigerant such as R404A, R507A, R508B, R410A, or hydrocarbon as a working fluid.

  The scroll compressor 50 includes in the sealed container 1 an electric motor 2 and a scroll compression mechanism 5 that compresses refrigerant between the orbiting scroll 3 driven by the electric motor 2 and the fixed scroll 4 that is a non-orbiting scroll. Arranged. The scroll compression mechanism 5 supports and guides the rotation of the orbiting scroll 3 between the fixed scroll 4 and the fixed member 7 fixed to the sealed container 1 so that the orbiting scroll 3 does not rotate relative to the fixed scroll 4. The Oldham ring 6 is provided.

  In the present embodiment, the scroll compressor 50 is a horizontal installation type, and the scroll compression mechanism 5 is disposed on the left side of the sealed container 1 on the drawing, and the compression mechanism 5 is driven on the right side of the sealed container 1. The electric motor 2 is arranged, and the rightmost part has a configuration in which lubricating oil is sealed in an oil reservoir 8. The scroll compressor 50 includes an oil supply mechanism that supplies lubricating oil to a lubrication target portion. This oil supply mechanism sucks the lubricating oil in the oil sump 8 through the oil supply piece 9 to the scroll compression mechanism 5 that must seal the bearings and refrigerant that are sliding parts to be lubricated, and the inside of the crankshaft 16 is absorbed. It supplies through the oil hole 10 which penetrates.

  In the scroll compression mechanism 5, the wrap of the fixed scroll 4 and the orbiting scroll 3 is engaged. As the electric motor 2 rotates, the orbiting scroll 3 is orbitally driven through the Oldham ring 6 and revolves. Due to the orbiting motion of the orbiting scroll 3, several compression chambers 11 formed between the laps of both the orbiting scroll 3 and the fixed scroll 4 have an inner lap side leading to the discharge port 13 from the outer lap side leading to the suction port 12. The volume is reduced and compressed while moving. The compression chamber 11 is composed of a sealed space 17. The refrigerant is supplied to the air-conditioning refrigeration cycle (not shown) from the discharge pipe 14 extending outside the sealed container 1, and then returned to the suction pipe 15 to circulate in the cycle. The refrigeration cycle is established by continuously executing the above series of operations.

  Next, the compression operation of the scroll compressor 50 configured as described above will be described with reference to FIGS. 1 and 2. FIG. 2 is a diagram for explaining the principle of compression operation of the scroll compressor 50 of this embodiment.

When the crankshaft 16 is rotated by driving the electric motor 2, the Oldham ring 6 causes the orbiting scroll 3 to orbit with respect to the fixed scroll 4, and the compression chamber formed by the two scrolls 3 and 4. As 11 moves to the center, its volume decreases. In other words, the orbiting scroll 3 relative to the fixed scroll 4, without changing its attitude, the crank angle phi = 0 ° in FIG. 2, 90 °, 180 °, about the center of the fixed scroll 4, as shown as 270 ° The revolving motion (turning motion with a predetermined crank radius ε) is performed. At this time, the volume of the sealed space 17 that is the crescent-shaped compression chamber 11 formed by the scrolls 3 and 4 is reduced, and the working fluid sucked into the sealed space 17 from the suction port 12 is compressed to discharge the discharge port. 13 is discharged into the sealed container 1. The fluid discharged into the sealed container 1 is discharged from the discharge pipe 14 to the outside. Further, when a compression action is performed by the compression mechanism, a force for separating the scrolls 3 and 4 is applied, but an intermediate pressure higher than the suction pressure and lower than the discharge pressure is applied to the back of the orbiting scroll 3. Therefore, the orbiting scroll 3 is pressed against the fixed scroll 4 by the intermediate pressure.

  The orbiting scroll 3 and the fixed scroll 4 have the same diameter r, declination angle θ, algebraic spiral coefficient a, and algebraic spiral index k in the polar coordinate format. In order to make the spiral a basic vortex curve and to increase the thickness of the spiral wall at the winding start portion, the value of the algebraic spiral coefficient a or the algebraic spiral index k is increased on the winding start portion side. .

r = a · θ ^k (1)
The inner curve and the outer curve of each of the orbiting scroll 3 and the fixed scroll 4 are constituted by the envelope of the basic vortex curve thus corrected. Thereby, both the thickness of the spiral wall of the orbiting scroll 3 and the fixed scroll 4 can be continuously changed from the start of the spiral to the end of the spiral. It can be made thin at the end of the winding where the thickness is low and the pressure is low.

  The algebraic spiral coefficient a or the algebraic spiral index k is increased only in a predetermined section of the deflection angle θ on the winding start side, and the algebraic spiral coefficient a or algebraic spiral in the other sections. The value of the index k may be constant.

  Next, the compressor performance based on the ratio of the planar area of the minimum sealed spaces 18 and 19 and the opening area of the discharge port when the sealed space 17 starts to communicate with the discharge port will be described with reference to FIGS. To do. 3 is a detailed view near the scroll wrap in the scroll compressor 50 of the present embodiment, FIG. 4 is a detailed view near the scroll wrap in the scroll compressor 50 of the comparative example, and FIG. 5 is a scroll compression including the present embodiment and the comparative example. 3 is a characteristic diagram of a compressor performance coefficient of the machine 50. FIG.

  FIG. 3 shows an example of this embodiment in which the ratio of the planar area of the minimum sealed spaces 18 and 19 to the opening area of the discharge port 13 is 5.8. The planar area of the minimum sealed spaces 18 and 19 is an area when the minimum sealed spaces 18 and 19 are projected onto the surface of the end plate, and the opening area of the discharge port 13 is the opening of the discharge port 13 to the end plate. It is an area when projected on the surface of the end plate in the part. Specifically, the ratio of the projected area of the minimum sealed space and the projected area of the discharge port when the previous sealed space 17 ends communicating with the discharge port 13 and when the next sealed space 17 starts communicating with the discharge port 13 is set. It is a circular discharge port such as 5.8. That is, after the scroll wrap forms the pair of minimum sealed spaces 18 and 19, the gas compressed by the swirling motion is the discharge port 13 and the discharge port in which the ratio of the minimum sealed space projection area to the discharge port projection area is 5.8. 13 outlines flow out to the discharge port 13 through a flow path formed by entering the first space 18 side. Further, since the discharge port 13 of the present embodiment has a circular shape, it is very easy to manufacture the discharge port 13 as compared with the conventional example in which the discharge port shape is an ellipse, a polygon or the like.

  FIG. 4 shows a comparative example in which the ratio of the planar area of the minimum sealed spaces 18 and 19 to the opening area of the discharge port 13 is 3.7. In the case of this comparative example, the communication start timing is earlier than when the ratio of this embodiment is 5.8, so that the minimum sealed spaces 18 and 19 formed by both scroll wraps 3 and 4 are larger. Accordingly, the set volume ratio becomes small, and in the high pressure ratio operation, the performance decreases due to the increase in the illustrated power due to insufficient compression. On the other hand, since the discharge port diameter can be increased, there is an effect of reducing the flow path loss resistance when discharging and improving the performance.

  Table 1 shows the efficiency of the illustration by the ratio of the projected area of the minimum sealed space and the discharge port in FIGS. 3 and 4, the theoretical value and the measurement result of the flow loss resistance, the compressor performance coefficient, and the efficiency of the other ratios.・ Shows the calculation results of theoretical values of flow loss resistance and compressor performance coefficient. The measured value is when the operating pressure ratio is 9.5, which corresponds to the condition that the set volume ratio assumed in the present invention is insufficient.

  As a result, compared with the case where the ratio of the projected area of the minimum sealed space to the projected area of the discharge port is 3.7, the improvement of the set volume ratio at 5.8 is the increase of the flow path loss resistance at the discharge port. Since it exceeded, there was an effect of improving the performance. FIG. 5 shows the compressor coefficient of performance including the calculation results based on other ratios.

As is apparent from FIG. 5, it was found that the compressor performance coefficient was remarkably improved when the ratio of the minimum sealed space projected area to the discharge port projected area was in the range of 5.0 to 8.0.
(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 6 is an enlarged view of the vicinity of the discharge port of the scroll compressor according to the second embodiment of the present invention. The second embodiment is different from the first embodiment in the points described below, and the other points are basically the same as those in the first embodiment, and thus redundant description is omitted.

  In the second embodiment, the discharge port 13 is enlarged so that the area on the discharge side is larger than the opening area to the sealed space 17, and includes a small diameter portion 13a and a large diameter portion 13b. Thus, by enlarging the middle of the discharge port 13, the flow path loss resistance can be reduced, and the compressor performance coefficient can be further improved.

It is sectional drawing of the scroll compressor of 1st Embodiment of this invention. It is a top view for showing the compression operation principle of a 1st embodiment. It is a detailed front view near the discharge outlet of the scroll wrap in 1st Embodiment of this invention. It is a detailed front view near the discharge port of the scroll lap in a comparative example. It is a figure which shows the compressor performance of a scroll compressor. It is a detailed sectional view near the discharge port of the scroll wrap in the scroll compressor of the second embodiment of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Sealed container, 2 ... Electric motor, 2a ... Rotor, 2b ... Stator, 3 ... Orbiting scroll, 4 ... Fixed scroll, 5 ... Compression mechanism, 6 ... Oldham ring, 7 ... Fixed member, 8 ... Oil sump, 9 DESCRIPTION OF SYMBOLS ... Oil supply piece, 10 ... Oil hole, 11 ... Compression chamber, 12 ... Suction port, 13 ... Discharge port, 14 ... Discharge pipe, 15 ... Suction pipe, 16 ... Crankshaft, 17 ... Sealed space, 18 ... Minimum sealed space, 19 ... Minimum enclosed space.

Claims (3)

A orbiting scroll and a fixed scroll having a spiral wrap formed upright on the end plate, and combining both the scrolls with the respective wraps facing inward, and the wrap outer wall surface side of the orbiting scroll and the scroll A sealed space is formed by the respective wraps and the end plate on the inner wall side of the wrap of the fixed scroll, and the volume of the sealed space is reduced as it moves in the center direction by the relative movement of the scrolls, and the outer circumferences of the scrolls In the scroll compressor that compresses the gas sucked from the side and discharges it from the discharge port provided in the center of the scroll,
The fixed scroll and the orbiting scroll use an algebraic spiral curve represented by the equation r = a · θk in a polar coordinate format with a radius r, a declination θ, an algebraic spiral coefficient a, and an algebraic spiral index k. together and a spiral wrap had, stroke volume in the range of 5～25Cm ^3, the ratio of the open area of the planar area discharge port of the smallest enclosed space when the enclosed space is started communicating with the discharge port A scroll compressor characterized by being in the range of 5.8 to 7.7 . 2. The scroll compressor according to claim 1, wherein any one of R404A, R507A, R508B, R410A, and hydrocarbon is used as a working fluid to be compressed. 3. The scroll compressor according to claim 1, wherein the discharge port is enlarged so that an area on the discharge side is larger than an opening area to the sealed space .

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