JP2011220229A - Scroll compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a scroll compressor which can provide ability as being set upon unloading and which can improve compression efficiency.SOLUTION: In the scroll compressor in which a capacity control mechanism that makes a pushing amount variable is provided, the capacity control mechanism has refrigerant sucking ports 10A and 10B for sucking a refrigerant into a compression chamber 6 at a position inner periphery side from an outermost periphery of the scroll as well as sucking the refrigerant into the compression chamber 6 from the outermost periphery of the scroll, and a capacity switching section 12 switches sucking of the refrigerant from the refrigerant sucking ports 10A and 10B and sucking of the refrigerant from the outermost periphery of the scroll.

Description

  The present invention relates to a scroll compressor provided with a capacity control mechanism that varies a displacement amount.

  2. Description of the Related Art A scroll compressor having a capacity control mechanism capable of varying a displacement amount according to a required capacity has been conventionally known. For example, as disclosed in Patent Document 1, such a scroll compressor capacity control mechanism generally employs a method of reducing the amount of displacement by relieving the refrigerant being compressed to the low pressure side. For this reason, a relief port communicating with the compression chamber is provided in the middle of the spiral direction of the scroll, and a configuration in which the refrigerant in the middle of compression is relieved to the low pressure side through the relief port is adopted so that the capacity can be reduced.

Japanese Patent Laid-Open No. 7-12060

  However, as described above, when the refrigerant that is being compressed is relieved to the low pressure side via the relief port, the amount of refrigerant relief is reduced by that amount due to the occurrence of pressure loss in the relief path. For this reason, there has been a problem that the capacity is more than the set capacity even though unloading is performed via the capacity control mechanism. Moreover, since the design pressure ratio does not change during full load or unload, there is a problem that the compression efficiency decreases during unload.

  The present invention has been made in view of such circumstances, and provides a scroll compressor capable of obtaining a set capability at the time of unloading and improving compression efficiency. With the goal.

In order to solve the above problems, the scroll compressor of the present invention employs the following means.
That is, the scroll compressor according to the present invention is a scroll compressor provided with a capacity control mechanism that varies the amount of displacement, wherein the capacity control mechanism is not limited to sucking refrigerant from the outermost periphery of the scroll into the compression chamber. A refrigerant suction port for sucking refrigerant into the compression chamber at a position on the inner peripheral side from the outermost periphery, and capacity switching means for switching between refrigerant suction from the refrigerant suction port and refrigerant suction from the outermost periphery of the scroll It is characterized by.

  According to the present invention, the capacity control mechanism has a refrigerant suction port for sucking the refrigerant into the compression chamber at a position on the inner peripheral side of the scroll outermost periphery, in addition to sucking the refrigerant from the outermost scroll outer periphery to the compression chamber, Since it has capacity switching means for switching between refrigerant suction from the refrigerant suction port and refrigerant suction from the outermost periphery of the scroll, the refrigerant is sucked from the outermost periphery of the scroll into the compression chamber during full load by the capacity switching means. When the compressor is compressed and unloaded, the refrigerant suction port is switched to the inner peripheral side of the scroll outermost periphery, and the refrigerant is sucked into the compression chamber and compressed to make the displacement amount of the compressor variable. Capacity can be controlled. Therefore, at the time of unloading, the refrigerant is not sufficiently relieved due to the pressure loss of the relief path as in the method of relieving the refrigerant in the middle of compression, so that the capacity does not go beyond the set value as it is set. Unload rate can be obtained. Further, since the design pressure ratio can be reduced during unloading, the compression efficiency under intermediate conditions (low load conditions) can be improved.

  Furthermore, the scroll compressor according to the present invention is characterized in that, in the scroll compressor, the capacity switching means is provided close to the refrigerant suction port.

  According to the present invention, since the capacity switching means is provided close to the refrigerant suction port, the dead volume formed by drilling the refrigerant suction port can be made as small as possible. Therefore, it is possible to minimize the influence on the compression performance due to the dead volume of the refrigerant suction port during full load.

  Furthermore, in the scroll compressor according to the present invention, in any one of the scroll compressors described above, a relief port connected to the suction outermost periphery of the scroll is provided between the outermost periphery of the scroll and the refrigerant suction port. It is characterized by that.

  According to the present invention, since the relief port connected to the suction outermost area of the scroll is provided between the scroll outermost periphery and the refrigerant suction port, depending on the position of the refrigerant suction port provided on the inner peripheral side, the scroll outermost periphery There is a case where a compression chamber is formed and a compression loss occurs due to an increase in pressure in the compression chamber. However, the pressure in the compression chamber is controlled by the relief port provided between the outermost scroll periphery and the refrigerant suction port. Relief to the inhalation area. Therefore, the occurrence of compression loss during unloading can be suppressed.

  According to the present invention, the refrigerant is sucked into the compression chamber from the outermost periphery of the scroll for compression at the full load by the capacity switching means and compressed to the refrigerant suction port on the inner peripheral side from the outermost periphery of the scroll at unloading. By sucking and compressing the refrigerant from the refrigerant suction port into the compression chamber, the displacement of the compressor can be made variable and the capacity can be controlled, so as to relieve the refrigerant in the middle of unloading when unloading, The refrigerant is not sufficiently relieved due to the pressure loss in the relief path, and the capacity is not more than set, and the unload rate as set can be obtained. Further, since the design pressure ratio can be reduced during unloading, the compression efficiency under intermediate conditions (low load conditions) can be improved.

It is a section lineblock diagram at the time of a full load of the principal part of the scroll compressor concerning a 1st embodiment of the present invention. It is a top view of the principal part of the scroll compressor shown in FIG. It is a cross-sectional block diagram at the time of the unloading of the principal part of the scroll compressor shown in FIG. It is a top view of the principal part of the scroll compressor shown in FIG.

Embodiments according to the present invention will be described below with reference to the drawings.
[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 4.
FIG. 1 shows a cross-sectional configuration diagram of the main part of the scroll compressor according to the first embodiment of the present invention at full load, and FIG. 2 shows a plan view thereof.
The compression mechanism 1 of the scroll compressor is composed of a pair of fixed scrolls 2 and a turning scroll 3 as is well known.

  The fixed scroll 2 is configured such that a fixed spiral wrap 2B is erected on one side surface of the fixed end plate 2A, and is fixedly installed in a housing (not shown). A fixed end plate 2 </ b> A of the fixed scroll 2 is provided with a discharge port 4 for discharging compressed gas in the vicinity of the center thereof, and a discharge valve 5 for opening and closing the discharge port 4.

  The orbiting scroll 3 has a structure in which an orbiting spiral wrap 3B is erected on one side surface of the orbiting end plate 3A, and a thrust bearing provided on the housing side (not shown) prevents rotation such as Oldham link or pin ring. It is connected to the crankshaft so as to be driven to revolve while being prevented from rotating through a mechanism.

  The fixed scroll 2 and the orbiting scroll 3 are meshed so that the fixed spiral wrap 2B and the orbiting spiral wrap 3B are opposed to each other and shifted in phase by 180 ° so that a pair of compression chambers 6 are formed therebetween. The compression mechanism 1 is configured. The fixed scroll 2 and the orbiting scroll 3 of this embodiment are provided with a step portion in the middle of the direction of the spiral, and the height of the fixed spiral wrap 2B and the swirl spiral wrap 3B is higher on the outer peripheral side than the step portion. The scroll is a stepped scroll with the side lowered, and is configured to be three-dimensionally compressible in both the circumferential direction and the axial direction.

  A suction region 7 is formed on the outer periphery of the outermost peripheral end of the fixed spiral wrap 2 </ b> B of the fixed scroll 2, and a refrigerant suction port 8 for full load is opened in the suction region 7. A refrigerant suction pipe 9 is connected to the refrigerant suction port 8. Further, refrigerant suction ports 10A and 10B for unloading are formed at positions on the inner peripheral side of the outermost peripheral end of the fixed spiral wrap 2B. In the present embodiment, the refrigerant suction ports 10A and 10B are each divided into three small holes so as to communicate with the compression chamber 6 at positions on the inner peripheral side of the stepped portion. The part is perforated so as to cover the wall surface of the fixed spiral wrap 2B.

  A branch suction pipe 11 branched from the refrigerant suction pipe 9 is connected to the refrigerant suction ports 10A and 10B for unloading, and a capacity switching means 12 for switching the refrigerant suction position is connected to the branch portion. A three-way switching valve 12A is provided. It is desirable to provide the three-way switching valve 12A as close to the refrigerant suction ports 10A and 10B as possible. In addition, the three-way switching valve 12A may be configured by two electromagnetic valves provided separately in the refrigerant suction pipe 9 and the branch suction pipe 11, and in this case, the electromagnetic valve provided in the branch suction pipe 11 is possible. It is desirable to provide as close to the refrigerant suction ports 10A and 10B as possible.

With the configuration described above, according to the present embodiment, the following operational effects can be obtained.
At the time of full load, the three-way switching valve 12A which is the capacity switching means 12 is switched to the refrigerant suction pipe 9 side as shown in FIG. As a result, the refrigerant is sucked into the suction area 7 formed in the fixed scroll 2 from the refrigerant inlet 8 for full load, and sucked into the compression chamber 6 from the outermost periphery of the fixed scroll 2 and the orbiting scroll 3. Is done. A pair of shaded compression chambers 6 </ b> A shown in FIG. 2 shows the compression chamber 6 </ b> A in a state where suction is cut off at the outermost periphery of the fixed scroll 2 and the orbiting scroll 3.

  When the orbiting scroll 3 is driven to revolve orbit, the compression chamber 6A that has been closed by suction is moved to the center side while gradually reducing its volume, and when the compression chamber 6 communicates with the discharge port 4, The compressed refrigerant gas pushes out the discharge valve 5 and is discharged into a discharge chamber (not shown), and is sent out of the compressor from there. As a result, the scroll compressor is set to a full load operation and exhibits the maximum capacity corresponding to the rotational speed.

  On the other hand, when the unload signal from the control means is input to the three-way switching valve 12A as the capacity switching means 12, the three-way switching valve 12A is switched to the branch intake pipe 11 side as shown in FIG. As a result, the refrigerant is sucked into the pair of compression chambers 6B formed on the inner peripheral side from the outermost periphery of the fixed scroll 2 and the orbiting scroll 3 from the refrigerant intake ports 10A and 10B for unloading. The compression chamber 6B is a compression chamber 6B formed on the inner peripheral side of the stepped portions of the shaded fixed scroll 2 and the orbiting scroll 3 shown in FIG. 4, and the fixed scroll 2 and the orbiting scroll shown in FIG. Compared with the compression chamber 6A formed on the outermost periphery of No. 3, the compression chamber 6B has a sufficiently small volume.

  Refrigerant compression at the time of unloading starts from this position, and when the orbiting scroll 3 is driven to revolve orbit, the compression chamber 6B is moved to the center side while the volume is gradually reduced, and the compression chamber 6 discharges. When communicating with the outlet 4, the compressed refrigerant gas pushes out the discharge valve 5 and is discharged into a discharge chamber (not shown), and is sent out of the compressor from there. As a result, the scroll compressor is unloaded and the amount of displacement is reduced.

  In this way, instead of the capacity control in which the refrigerant gas being compressed is relieved to the low pressure side, the refrigerant is sucked by the three-way switching valve 12A during unloading, which is provided on the inner peripheral side of the scroll outermost periphery. By switching to suction from the refrigerant suction ports 10A and 10B for loading, and sucking and compressing the refrigerant into the compression chamber 6 from the refrigerant suction ports 10A and 10B, the displacement amount can be varied and the capacity can be controlled. ing. For this reason, when unloading, the refrigerant is not sufficiently relieved due to the pressure loss of the relief path as in the method of relieving the refrigerant in the middle of compression, and the capacity does not go beyond the set value as it is set. The unload rate can be obtained. Further, since the design pressure ratio can be reduced during unloading, the compression efficiency can be improved particularly under intermediate conditions (low load conditions).

  Further, since the three-way switching valve 12A as the capacity switching means 12 is provided as close as possible to the refrigerant suction ports 10A and 10B for unloading, it is formed by drilling the refrigerant suction ports 10A and 10B. Dead volume can be reduced as much as possible. Thereby, it is possible to minimize the influence on the compression performance due to the dead volume of the refrigerant suction ports 10A and 10B for full load and unload.

  Further, the refrigerant suction ports 10A and 10B for unloading are provided on the inner peripheral side with respect to the stepped portion of the stepped scroll. For this reason, the compression chamber 6 at the time of unloading does not include a stepped portion, so that refrigerant leakage from the stepped portion can be eliminated, and the compression efficiency at the time of unloading can be further improved.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS.
This embodiment is different from the first embodiment described above in that relief ports 13A and 13B are provided. Since other points are the same as those in the first embodiment, description thereof will be omitted.
In this embodiment, the compression chamber 6 is formed on the outermost periphery of the scroll depending on the position of the refrigerant suction ports 10A and 10B on the inner peripheral side, and a compression loss may occur due to the pressure increase in the compression chamber 6, so that the fixed vortex By providing relief ports 13A and 13B that are connected to the suction area 7 on the outermost periphery of the scroll between the outermost peripheral ends of the cylindrical wrap 2B and the swirl spiral wrap 3B and the refrigerant suction ports 10A and 10B on the inner peripheral side, The pressure in the compression chamber 6 can be relieved to the suction area 7.

  Thus, by providing the relief ports 13A and 13B connected to the outermost scroll suction area 7 between the scroll outermost periphery and the refrigerant suction ports 10A and 10B, the positions of the refrigerant suction ports 10A and 10B on the inner peripheral side are provided. In some cases, the compression chamber 6 is formed on the outermost periphery of the scroll and a compression loss may occur, but the pressure in the compression chamber 6 is applied to the suction region 7 on the outermost periphery of the scroll via the relief ports 13A and 13B. Relief is possible. For this reason, generation | occurrence | production of the compression loss at the time of unloading can be suppressed.

  In addition, this invention is not limited to the invention concerning the said embodiment, In the range which does not deviate from the summary, it can change suitably. For example, the switching of the three-way switching valve 12A, which is the capacity switching means 12, may be switched automatically by detecting the pressure, or may be switched electrically by a demand signal. For this reason, as the three-way switching valve 12A, a pressure type automatic capacity control valve may be used, or an electromagnetic type switching valve may be used.

  Further, as the scroll compressor, a sealed electric scroll compressor of a type in which the crankshaft is driven by a motor in which the compression mechanism 1 is built in the housing, or a drive source is not built in, and the crankshaft is in the housing. Any of the open scroll compressors of the type that protrudes to the outside and is driven by an external drive source may be used.

DESCRIPTION OF SYMBOLS 1 Compression mechanism 2 Fixed scroll 3 Revolving scroll 6, 6A, 6B Compression chamber 10A, 10B Refrigerant suction port (for unloading)
12 Capacity switching means 12A Three-way switching valve 13A, 13B Relief port

Claims (3)

In a scroll compressor provided with a capacity control mechanism that varies the amount of displacement,
The capacity control mechanism has a refrigerant suction port for sucking refrigerant into the compression chamber at a position on the inner peripheral side of the scroll outermost periphery, in addition to sucking refrigerant into the compression chamber from the outermost periphery of the scroll,
A scroll compressor comprising capacity switching means for switching between refrigerant suction from the refrigerant suction port and refrigerant suction from the outermost periphery of the scroll.   The scroll compressor according to claim 1, wherein the capacity switching means is provided close to the refrigerant suction port. 3. The scroll compressor according to claim 1, wherein a relief port is provided between the outermost periphery of the scroll and the refrigerant suction port, the relief port being connected to the suction area of the outermost periphery of the scroll.

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