JPH06294389A - Scroll compressor - Google Patents

Abstract

PURPOSE:To prevent the generation of excessive compression in low compression ratio condition driving of a scroll compressor. CONSTITUTION:A discharge port 18 for communicating a high pressure chamber 9 in a closed container with a compression space 17 is formed in the center of the end plate 11 of a fixed scroll 7. Auxiliary discharge ports 21, 21 positioned on the outer side of the discharge port 18, and for communicating the high pressure chamber 9 with the compression space 17 are formed on the end plate 11 of the fixed scroll 7. A discharge valve 22 and an excessive compression preventing valve 23 for respectively blocking the discharge port 18 and auxiliary discharge ports 21, 22 from the high pressure chamber 9 side are provided. The discharge valve 22 and the excessive compression preventing valve 23 release the discharge port 18 or the auxiliary discharge ports 21, 21 respectively when a pressure in the compression space 17 is raised to that of the high pressure chamber 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scroll compressor used in refrigeration / air-conditioning equipment and the like, which performs compression by engaging a fixed scroll and an orbiting scroll.

[0002]

2. Description of the Related Art A conventional general scroll compressor is disclosed, for example, in Japanese Patent Laid-Open No. 3-246388 (F04C18 / 0).
As shown in 2), an electric element having a rotary shaft in a closed container, an orbiting scroll driven by this electric element and having a spiral wrap standing on the end plate, and an orbiting scroll. The fixed scroll in which spiral wraps are erected on the end plates that face each other is housed, and the orbiting scroll is orbited while revolving so as not to rotate with respect to the fixed scroll. The plurality of compression spaces formed are gradually reduced from the outside to the inside to perform compression.

A discharge port (discharge port) is formed in the central portion of the end plate of the fixed scroll so as to connect the high pressure chamber in the closed container with the compression space. Set compression ratio (high pressure / low pressure)
The high pressure gas refrigerant is discharged into the high pressure chamber from the discharge hole through the discharge hole, and the high pressure gas refrigerant is discharged into the refrigerant circuit through the discharge pipe provided in communication with the high pressure chamber.

[0004]

However, when such a scroll compressor is operated under a low compression ratio condition such as a compression ratio of 2 which is lower than the compression ratio of 3, an overcompression occurs between the fixed scroll and the orbiting scroll. Occurs, which increases the input (compression work), reduces the coefficient of performance, deteriorates the characteristics of the compressor, and increases the load applied to the bearings and the like of the electric elements in the closed container.

An object of the present invention is to prevent the above-mentioned inconvenience by preventing over-compression from occurring when the scroll compressor operates under a low compression ratio condition.

[0006]

A scroll compressor SC of the present invention is an electric element 3 having a rotary shaft 5 in a closed container 1.
When driven by the electric element 3, the orbiting scroll 8 in which the end plate 14 is provided with a spiral wrap 15 and the end plate 11 facing the orbiting scroll 8 is engaged with the spiral wrap 13. The fixed scroll 7 is housed and the plurality of compression spaces 17 formed by the fixed scroll 7 and the orbiting scroll 8 are gradually contracted from the outside to the inside to perform compression. To orbit the fixed scroll 7 while revolving, and a discharge port 18 which is formed in the center of the end plate 11 of the fixed scroll 7 and connects the high pressure chamber 9 in the closed container 1 with the compression space 17. An auxiliary discharge port 21, which is formed on the end plate 11 of the fixed scroll 7 outside the discharge port 18 and connects the high pressure chamber 9 and the compression space 17,
21, discharge port 18 and auxiliary discharge ports 21, 21
Is provided with a discharge valve 22 and an overcompression prevention valve 23 that close each from the high pressure chamber 9 side, and the discharge valve 22 and the overcompression prevention valve 23 increase the pressure of the compression space 17 to the pressure of the high pressure chamber 9. In this case, the discharge port 18 or the auxiliary discharge ports 21 and 21 are opened, respectively.

[0007]

According to the scroll compressor SC of the present invention, for example, when the compression ratio is set to 3 during normal operation (high pressure is 18 kg / cm ² and low pressure is 6 kg / cm ² ), the high pressure chamber 9 in the closed container 1 The set pressure of is 18 kg / cm ² . By swinging the orbiting scroll 8 with respect to the fixed scroll 7,
Compression space 1 between the wraps 13 and 15 of both scrolls 7 and 8
7 is gradually compressed from the outside to the inside, and when the pressure reaches the pressure of the high pressure chamber 9 at the position of the discharge port 18 at the central portion, the discharge valve 22 closing the discharge port 18 opens and compresses. The generated gas is discharged into the high pressure chamber 9. At this time, the auxiliary discharge port 2 located outside the discharge port 18
In Nos. 1 and 21, the pressure in the compression space 17 has not yet reached the pressure in the high-pressure chamber 9, so the overcompression prevention valve 23 closes the auxiliary discharge ports 21 and 21, and normal operation is performed.

Next, the compression ratio is set to 2 (high pressure is 12 kg).
/ Cm ² and the low pressure is 6 kg / cm ² ) and the low compression ratio condition, the set pressure of the high pressure chamber 9 in the closed container 1 is 12
It becomes kg / cm ² . In this case as well, when the orbiting scroll 8 revolves with respect to the fixed scroll 7, the compression space 17 between the wraps 13 and 15 of both scrolls 7 and 8 is gradually compressed from the outside to the inside. When the pressure in the compression space 17 reaches the pressure in the high-pressure chamber 9 at the position of the auxiliary discharge ports 21, 21, the auxiliary discharge ports 21, 2
The overcompression prevention valve 23 closing 1 is opened, and gas is started to be discharged from the auxiliary discharge ports 21 and 21 to the high pressure chamber 9. Then, the discharge valve 22 that closes the discharge port 18 in the central portion
Since the gas is also opened, the gas is also discharged from this discharge port 18, which prevents overcompression,
The deterioration of the characteristics is prevented and the normal operation is performed.

[0009]

Embodiments of the present invention will be described in detail below with reference to FIGS. FIG. 3 shows a vertical side view of the scroll compressor SC of the present invention. In FIG. 3, 1 is a closed container, and inside this closed container 1 is a scroll compression element 2 on the upper side.
However, the electric elements 3 for driving the scroll compression element 2 are housed on the lower side. Reference numeral 4 denotes a frame, and the frame 4 pivotally supports a rotating shaft 5 of the electric element 3 at a central portion.

The scroll compression element 2 is composed of a fixed scroll 7 and an orbiting scroll 8. The fixed scroll 7 includes a disk-shaped end plate 11 that divides the closed container 1 into a high-pressure chamber 9 and a low-pressure chamber 10, an annular wall 12 projecting from one end of the end face of the end plate 11, and the annular wall 12. It is composed of an involute shape or a spiral wrap 13 formed of a curve similar to this, which is surrounded and erected on the end plate 11. The fixed scroll 7 is provided with the annular wall 12 and the wrap 13 protruding downward.

The orbiting scroll 8 has a disk-shaped end plate 14,
A spiral wrap 1 which is formed on one surface of the end plate 14 and which is formed of an involute shape or a curve similar thereto.
5 and the pin portion 1 protruding from the center of the other surface of the end plate 14.
6 and 6. The orbiting scroll 8 is arranged so that the wrap 15 faces upward and engages with the wrap 13 of the fixed scroll 7 with the protruding direction of the wrap 15 facing upward, and a plurality of crescent-shaped compression spaces 17 are formed inside. . Further, the compression space 17 is gradually reduced from the outside to the inside to compress the sucked refrigerant.

Reference numeral 19 denotes a drive unit provided at the tip of the rotary shaft 5 and inserted into the pin portion 16 of the orbiting scroll 8. The center of the drive unit 19 is provided eccentrically with the axis of the rotary shaft 5. There is. An Oldham ring 20 revolves around a circular orbit so that the orbiting scroll 8 does not rotate with respect to the fixed scroll 7.

On the other hand, at the center of the end plate 11 of the fixed scroll 7, there is provided a discharge port 18 for connecting the compression space 17 and the high pressure chamber 9 as shown in FIG. Also, discharge port 1
Similarly, in the end plate 11 of the portion located outside of 8, the auxiliary discharge ports 21 and 21 that connect the compression space 17 (the compression space located outside the central compression space 17) and the high pressure chamber 9 to each other.
Are formed at symmetrical positions with the discharge port 18 in between.

As shown in FIG. 2, the discharge port 18 is closed from the high pressure chamber 9 side by a discharge valve 22 made of a disk-shaped thin plate, and the auxiliary discharge ports 21, 21 are made high pressure by an overcompression prevention valve 23 made of an annular thin plate. It is closed from the chamber 9 side. The discharge valve 22 and the overcompression prevention valve 23 are held on the end plate 11 by a disc-shaped guide 24, and both open when the pressure in the compression space 17 reaches the pressure in the high-pressure chamber 9 and the compression space 17 The high pressure chamber 9 is communicated.

A suction passage (not shown) for guiding the refrigerant to the scroll compression element 2 is provided on the outer peripheral portion of the frame 4. Further, 31 is a suction pipe attached to the closed container 1, and this suction pipe 31 is below the frame 4
It communicates with the low pressure chamber 10 inside. A discharge pipe 32 is attached to the upper part of the closed container 1, and the discharge pipe 32 communicates with the high pressure chamber 9 in the closed container 1.

The scroll compressor S having such a configuration
In C, when the electric element 3 is rotated, the orbiting scroll 8 is driven via the rotary shaft 5. That is, the orbiting scroll 8 is driven by the drive portion 19 (which is eccentric with respect to the axis of the rotary shaft 5) inserted into the pin portion 16,
The Oldham ring 20 orbits the fixed scroll 7 while revolving on a circular orbit so as not to rotate. Then, the fixed scroll 7 and the orbiting scroll 8 gradually reduce the compression space 17 formed between the wraps 13 and 15 from the outside to the inside. On the other hand, the refrigerant flowing from the suction pipe 31 into the low-pressure chamber 10 in the closed container 1 is guided to the compression space 17 of the scroll compression element 2 through the suction passage on the outer periphery of the frame 4, so that the refrigerant flows in the orbiting scroll 8. By turning, it is gradually compressed from the outside to the inside.

Here, the compression ratio of the scroll compressor SC during normal operation is 3 (high pressure is 18 kg / cm ² and low pressure is 6 k).
g / cm ² ), the set pressure in the high pressure chamber 9 is 18
It becomes kg / cm ² . Therefore, due to the orbiting of the orbiting scroll 8 with respect to the fixed scroll 7 as described above, the compression space 17 between the two wraps 13 and 15 is gradually compressed from the outside to the inside, and the position of the discharge port 18 at the center of the end plate 11 is increased. When the pressure reaches the pressure of the high pressure chamber 9, the discharge valve 22
The refrigerant gas that has been opened and compressed is discharged to the high-pressure chamber 9.
The refrigerant gas discharged into the high pressure chamber 9 is discharged from the discharge pipe 32 to the outside of the closed container 1.

At this time, in the auxiliary discharge ports 21 and 21 located outside the discharge port 18, the pressure in the compression space 17 has not reached the pressure (18 kg / cm ² ) in the high pressure chamber 9, so that overcompression is performed. The prevention valve 23 is the auxiliary discharge port 21.
Is closed, and the same operation as the conventional compressor without the auxiliary discharge ports 21 and 21 is performed.

Next, the compression ratio is set to 2 (high pressure is 12 kg).
When operating under a low compression ratio condition in which the low pressure is 6 kg / cm ² and the pressure is 6 kg / cm ² , the set pressure of the high pressure chamber 9 in the closed container 1 is 12 kg / cm ² . In this case as well, when the orbiting scroll 8 revolves with respect to the fixed scroll 7, the compression space 17 between the wraps 13 and 15 of both scrolls 7 and 8 is gradually compressed from the outside to the inside. The pressure of the compression space 17 at the position of the auxiliary discharge ports 21 and 21 is the pressure of the high pressure chamber 9 (12 kg / c).
m ² ), the overcompression prevention valve 23 that closes the auxiliary discharge ports 21, 21 opens and the auxiliary discharge ports 21, 2
Refrigerant gas begins to be discharged from 1 to the high-pressure chamber 9. afterwards,
Since the discharge valve 22 that closes the discharge port 18 at the central portion is also opened, the refrigerant gas is also discharged from this discharge port 18.

By opening the auxiliary discharge ports 21 and 21 as described above, over-compression of the scroll compression section 2 during the operation at such a low compression ratio is prevented, and therefore, an increase in the input (compression work) of the scroll compressor SC is prevented. As a result, the characteristic deterioration due to the reduction of the coefficient of performance is eliminated. Further, since the load applied to the frame 4 that receives the rotating shaft 5 of the electric element 3 is prevented from increasing, deterioration of the components of the scroll compressor SC can be suppressed and the life of the scroll compressor SC can be extended. Become.

In the above description, the discharge valve 22 and the overcompression prevention valve 23 are made of separate plate materials, but the present invention is not limited to this, and the discharge valve 22 and the discharge valve 22 are provided at the center as shown in FIGS. 4 and 5. The discharge valve 22 has an arc-shaped narrow connecting portion 25.
arc-shaped overcompression prevention valve 23 connected by a and 25a,
The discharge valve 22 and the overcompression prevention valves 23, 23 may be integrally configured by a valve body 25 having 23. With such a configuration, it is possible to reduce the number of parts. Also,
In each of the embodiments, the guide 24 is formed in a disc shape, but the present invention is not limited to this, and the guide 24 may be formed in an S shape substantially in accordance with the shape of the valve body 25 as shown in FIGS. 6 and 7.

[0022]

As described above in detail, according to the present invention, the pressure of the compression space at the auxiliary discharge port outside the discharge port becomes equal to the pressure of the high pressure chamber in the closed container during the low compression ratio operation of the compressor. When the temperature rises, the over-compression prevention valve opens the auxiliary discharge port and discharges the gas in the compression space into the high-pressure chamber, preventing over-compression from occurring between the fixed scroll and the orbiting scroll wrap. . Therefore, the input of the compressor (compression work) is prevented from increasing, the characteristic deterioration due to the reduction of the coefficient of performance can be eliminated, and the increase in the load applied to the rotary bearing of the electric element can be prevented. The life of the compressor can be extended.

[Brief description of drawings]

FIG. 1 is an enlarged vertical side view of a discharge port portion of a fixed scroll of a scroll compressor according to the present invention.

FIG. 2 is a plan view of a discharge port portion of a fixed scroll of the scroll compressor of the present invention.

FIG. 3 is a vertical cross-sectional side view of the scroll compressor of the present invention.

FIG. 4 is a plan view of a discharge port portion of a fixed scroll for explaining another embodiment of the scroll compressor of the present invention.

FIG. 5 is an enlarged vertical side view of a discharge port portion of the fixed scroll in the case of FIG.

FIG. 6 is a plan view of a discharge port portion of a fixed scroll for explaining still another embodiment of the scroll compressor according to the present invention.

FIG. 7 is an enlarged vertical side view of the discharge port portion of the fixed scroll in the case of FIG.

[Explanation of symbols]

 SC Scroll compressor 1 Airtight container 3 Electric element 5 Rotating shaft 7 Fixed scroll 8 Oscillating scroll 9 High pressure chamber 11 End plate 13 Wrap 14 End plate 15 Wrap 17 Compression space 18 Discharge port 21 Auxiliary discharge port 22 Discharge valve 23 Overcompression prevention valve

Claims (1)

[Claims] 1. An electric element having a rotary shaft in a hermetic container, an orbiting scroll driven by the electric element and having a spiral wrap standing on an end plate, and an end plate which faces and engages with the orbiting scroll. A fixed scroll in which a spiral wrap is erected is housed, and a plurality of compression spaces formed by the fixed scroll and the orbiting scroll are gradually reduced from the outside to the inside to perform compression, In a scroll compressor that orbits the orbiting scroll while revolving with respect to a fixed scroll, a discharge port that is formed at the center of the end plate of the fixed scroll and that communicates the high pressure chamber and the compression space in the closed container. An auxiliary discharge port formed outside the discharge port on the end plate of the fixed scroll for communicating the high pressure chamber with the compression space, and the discharge port. A discharge valve and an over-compression prevention valve for closing the auxiliary discharge port and the auxiliary discharge port from the high-pressure chamber side, respectively, and these discharge valve and over-compression prevention valve are provided when the pressure in the compression space rises to the pressure in the high-pressure chamber. In addition, the scroll compressor is characterized in that the discharge port or the auxiliary discharge port is opened.