ES2975080T3 - Scroll compressor with bypass port - Google Patents

Abstract

A scroll compressor capable of inhibiting the occurrence of pulsations of a fluid is provided. The scroll compressor includes: an on/off valve (38) that opens when capacity control operation of a fluid is activated, and returns a medium-compression fluid, which is discharged to an intermediate chamber (81), to a suction chamber (17); and a second check valve (42) that opens when the capacity control operation is turned off and when the pressure in the intermediate chamber (81) becomes greater than the pressure in a discharge chamber (16), and discharges the medium-compression fluid, which is discharged to the intermediate chamber (81), to the discharge chamber (16) through a discharge port (85). (Automatic translation with Google Translate, without legal value)

Description

DESCRIPTION

Scroll compressor with bypass port

Technical sector

The present invention relates to a scroll compressor.

State of the art

Conventionally, scroll compressors are sometimes used, for example, as outdoor units of commercial multiple air conditioners. In this case, a plurality of indoor units are connected to one scroll compressor.

In the commercial multi-air conditioner having the above constitution, the scroll compressor requires the ability to operate all indoor units, and also the ability to operate only one indoor unit. To provide these capabilities, the scroll compressor has a bypass port (a bypass hole) and a first check valve that opens/closes the bypass port (e.g., see Patent Document 1).

The bypass port passes through an end plate of a fixed coil which is located outside a discharge port provided in the end plate of the fixed coil. The first check valve is fixed to the first surface of the end plate of the fixed coil. The first check valve opens/closes the bypass port.

A fluid discharged from the bypass port returns a medium compression fluid (a refrigerant) to a suction space in a shell through a bypass line.

Among conventional scroll compressors, there is a compressor that has a discharge port and a second check valve.

The discharge port is provided to pass through an end plate of a fixed spiral which is located outside the discharge port. The second check valve is fixed to the first surface of the end plate of the fixed spiral and opens/closes the discharge port.

With this constitution, when a pressure difference between a discharge chamber, which is arranged inside an intermediate chamber in which the first check valve and the second check valve are arranged, and the intermediate chamber is small, the fluid can be drawn into a discharge space before the fluid is excessively compressed. Thus, excessive compression can be inhibited.

[Patent Documents]

[Patent Document 1] Japanese Patent Application Laid-Open, First Publication No. H08-61269

Documents EP1953388, EP2541066, EP2679823 and US2013/136640 disclose scroll compressors.Object of the invention

It is considered to connect a fluid supply line, which connects the discharge chamber and the indoor unit, and a branch line, which branches off from the bypass line, on the outside of the housing to also use the bypass port and the discharge port.

However, in this case, a compressed flow in the bypass line is caused to flow directly into the fluid supply line. This can cause fluid pulsation.

Therefore, an object of the present invention is to provide a scroll compressor capable of inhibiting the occurrence of pulsations of a fluid.

To solve the above problems, a scroll compressor according to claim 1 includes: a suction chamber into which a fluid is introduced; a discharge chamber configured to lead to a discharge pipe; a scroll compressor main body having a fixed scroll and an orbital scroll provided between the suction chamber and the discharge chamber and configured to discharge the fluid to be compressed from a discharge port, which is provided in the fixed scroll, to the discharge chamber; a bypass port configured to remove a medium compression fluid from the scroll compressor main body located outside the discharge port; an intermediate chamber provided between the scroll compressor main body and the discharge chamber and outside the discharge port; a first check valve configured to discharge the medium compression fluid to the intermediate chamber through the bypass port; an on/off valve configured to open when the fluid capacity control operation is turned on, and to return the medium compression fluid, which is discharged to the intermediate chamber, to the suction chamber; and a second check valve configured to open when the capacity control operation is turned off and when the pressure in the intermediate chamber becomes higher than the pressure in the discharge chamber, and to discharge the medium compression fluid, which is discharged to the intermediate chamber, to the discharge chamber through the discharge port.

According to the present invention, the discharge chamber is provided which communicates with the discharge pipe. Thereby, since the fluid discharged from the discharge port is guided into the discharge pipe after flowing through the discharge chamber, the fluid pulsation can be reduced in the discharge chamber. Thereby, the occurrence of fluid pulsation can be inhibited.

In the scroll compressor according to the aspect of the present invention, the first check valve is provided on the first surface of a fixed scroll end plate located near the discharge chamber.

In this way, the first check valve is provided on the first surface of an end plate of the fixed scroll located near the discharge chamber, and thus the medium compression fluid can be discharged to the intermediate chamber through the bypass port.

The scroll compressor according to the aspect of the present invention further includes a bypass line configured to guide the medium compression fluid, which is withdrawn from the bypass port, to the suction chamber. The on/off valve may be provided for the bypass line.

The bypass pipe having this constitution is provided, and the on/off valve is provided for the bypass pipe. In this way, the medium compression fluid discharged to the intermediate chamber can return to the suction chamber.

The scroll compressor according to the aspect of the present invention further includes a cover provided to face the single surface of the end plate and configured to define the intermediate chamber together with the fixed scroll end plate. The discharge port and the second check valve are provided for the cover.

In this way, the discharge port is provided for the cover, which is a different member from the end plate of the fixed spiral for which the bypass port is provided. In this way, a position at which the bypass port is formed and a position at which the discharge port is formed do not interfere with each other. Thus, the degree of freedom for the position at which the bypass port is formed and the degree of freedom for the position at which the discharge port is formed can be improved.

In the scroll compressor according to the aspect of the present invention, the cover may be a member formed in an annular shape surrounding a portion located outside the discharge port within the first surface of the end plate.

In this way, the cover is provided to surround the portion located outside the discharge port within the first surface of the end plate, and therefore, a region in which an outlet of the discharge port is formed and a region in which an outlet of the bypass port is formed can be separated from each other. In this way, the high-pressure fluid discharged from the discharge port and the low- or medium-pressure fluid (the fluid having a lower pressure than the fluid discharged from the discharge port) discharged from the bypass port can be prevented from mixing.

The cover is formed in the annular shape. In this way, the bypass port can be provided at a desired position of the fixed spiral in a circumferential direction of the fixed spiral. In this way, the degree of freedom for the position at which the bypass port is formed can be improved.

The scroll compressor according to the aspect of the present invention further includes a casing in which the scroll compressor main body and the cover are housed and which defines the discharge chamber together with the cover. The discharge pipe is provided for the casing to communicate with the discharge chamber, and the on/off valve is arranged outside the casing.

With this constitution, the discharge chamber can be defined by the casing and the cover. The on/off valve is provided outside the casing and thus the maintenance of the on/off valve can be improved.

In the scroll compressor according to the aspect of the present invention, the bypass port may be composed of a plurality of bypass ports provided in a circumferential direction of the fixed scroll, and the first check valve may be provided for each of the plurality of bypass ports. In this way, the plurality of bypass ports and the plurality of first check valves are provided in the circumferential direction of the fixed scroll. In this way, the fluid can be discharged to the intermediate chamber through the plurality of bypass ports.

In this way, the fluid discharged from the plurality of bypass ports can be guided to the discharge pipe through one discharge port, and thus, the constitution of the scroll compressor can be simplified.

In the scroll compressor according to the aspect of the present invention, when an opening area of the bypass port is defined as Sv, an opening area of the discharge port is defined as Sm, an opening area of the discharge port is defined as St, and an opening area of the discharge pipe is defined as Sf, the following formula (1) can be satisfied.

Sv<Sm<St<Sf............. (1)

In this way, to satisfy the above formula (1), Sv, Sm, St and Sf are set. In this way, the pressure loss can be reduced.

The scroll compressor according to the aspect of the present invention may further include a third check valve provided to the first surface of the fixed scroll end plate and configured to open the discharge port when a pressure at the discharge port is higher than a pressure in the discharge chamber. The third check valve may be lifted with more difficulty than the first check valve and the second check valve, and the second check valve may be lifted with more difficulty than the first check valve.

With this constitution, pressure loss can be reduced.

In the scroll compressor according to the aspect of the present invention, the discharge port may be arranged opposite to the discharge pipe in an extension direction of the casing.

The discharge port is provided in this position and hence the pressure loss can be reduced.

According to the present invention, a degree of freedom for a position where a bypass port is formed and a degree of freedom for a position where a discharge port is formed can be improved, and then the occurrence of pulsations of a fluid can be inhibited.

Description of the figures

Fig. 1 is a sectional view schematically showing a general constitution of the main sections of a scroll compressor according to a first embodiment of the present invention. Fig. 2 is an enlarged sectional view of a portion enclosed by a region A outside the scroll compressor shown in Fig. 1.

Figure 3 is an enlarged sectional view of a portion enclosed by a region B outside the scroll compressor shown in Figure 1.

Figure 4 is a schematic view showing a fluid capacity control operation and a full load operation in the scroll compressor shown in Figure 1.

Fig. 5 is a sectional view schematically showing an outline constitution of main sections of a scroll compressor according to a second embodiment of the present invention.Detailed Description of the Invention

Next, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

(First realization)

A scroll compressor 10 of a first embodiment of the present invention will be described with reference to Fig. 1. In Fig. 1, O1 indicates an axis (hereinafter referred to as "axis O1") of a rotary shaft main body 45, and O2 indicates an eccentric axis (hereinafter referred to as "eccentric axis O2") of an eccentric shaft 46.

The scroll compressor 10 has a casing 11, a suction pipe 12, a discharge pipe 14, a main bearing 21, a sub-bearing 22, a rotary shaft 23, an oil feed pump 24, a driver 25, a scroll compressor main body 26, a bushing assembly 28, an Oldham ring 31, a first check valve 32, a third check valve 33, a cover 35, a bypass pipe 37, an on/off valve 38, a support member 39, and a second check valve 42.

The casing 11 is formed in a sealed structure and has a hollow portion in an interior thereof. The casing 11 extends in a direction of the axis O1. The casing 11 has a first end 11A at which the discharge pipe 14 is provided, and the second end 11B. The first end 11A and the second end 11B are arranged in the direction of the axis O1.

The casing 11 houses the main body 26 of the scroll compressor and the cover 35. The inside of the casing 11 is divided into a discharge chamber 16 and a suction chamber 17 by the main body 26 of the scroll compressor. The discharge chamber 16 is divided between the first end 11A of the casing 11 and the cover 35. A part of the suction chamber 17 is divided by the second end 11B and the middle of the casing 11.

The suction pipe 12 is provided in a middle side wall of the housing 11. The suction pipe 12 leads to the suction chamber 17. The suction pipe 12 introduces a fluid (e.g., a refrigerant gas which is a working fluid) into the suction chamber 17 from the outside of the housing 11.

The discharge pipe 14 is provided at the first end 11A of the casing 11. The discharge pipe 14 communicates with the discharge chamber 16. When the scroll compressor 10 is used as an outdoor unit of a commercial multiple air conditioner, the discharge pipe 14 is connected to, for example, a plurality of indoor units (not shown), which are places of use.

A compressed fluid (hereinafter referred to as "high-pressure fluid") is discharged from a discharge port 55 constituting the main body of the scroll compressor 26, and then discharged to the discharge pipe 14 through the discharge chamber 16. The discharged high-pressure fluid is supplied to the places of use.

The main bearing 21 is housed in the casing 11 and is fixed to an inner wall of the casing 11. The main bearing 21 is disposed between a position where the suction pipe 12 and the casing 11 and the main body 26 of the scroll compressor are connected.

The main bearing 21 supports a first end 45A of the rotary shaft main body 45 extending in the direction of the O1 axis in a rotating state.

The sub bearing 22 is housed in the casing 11. The sub bearing 22 is fixed to an inner wall of the casing 11 which is located closer to the second end 11B than the main bearing 21. The sub bearing 22 supports the second end 45B of the rotary shaft main body 45 extending in the direction of the O1 axis in a rotating state.

The rotary shaft 23 has the rotary shaft main body 45 and the eccentric shaft 46. The rotary shaft main body 45 is formed in the form of a column. The rotary shaft main body 45 has a first end 45A disposed near the scroll compressor main body 26, and the second end 45B disposed near the second end 11B of the casing 11.

The rotary shaft main body 45 is supported by the main bearing 21 and the sub bearing 22 in a state where it can rotate around the axis O1.

The eccentric shaft 46 is provided at the other end (a tip of the first end 45A) of the rotary shaft main body 45. The eccentric shaft 46 uses the eccentric shaft O2, which is offset from the axis O1 (located away from the axis O1), as a central axis. The eccentric shaft 46 is a columnar shaft having a smaller outer diameter than the rotary shaft main body 45.

When the rotary shaft main body 45 rotates around the O1 axis, the eccentric shaft 46 configured in this manner rotates about the O1 axis.

The oil feed pump 24 is provided below the sub-bearing 22. The oil feed pump 24 supplies a lubricant to a main bearing body constituting the main bearing 21 and the sub-bearing 22.

The actuator 25 is housed in the housing 11. The actuator 25 is arranged to surround an outer circumferential surface of the middle section of the rotary shaft main body 45. The actuator 25 rotates the rotary shaft main body 45. For example, an electric generator may be used as the actuator 25.

The main body 26 of the scroll compressor is housed in the casing 11 and is provided between the main bearing 21 and the discharge chamber 16 (between the suction chamber 17 and the discharge chamber 16). The main body 26 of the scroll compressor has a fixed scroll 48 and an orbital scroll 49.

The fixed scroll 48 is arranged between the orbital scroll 49 and the discharge chamber 16. The fixed scroll 48 has an end plate 51 and a fixed casing 53.

The end plate 51 is a disk-shaped plate and is fixed to the inner wall of the casing 11. The end plate 51 has a first surface 51a, a second surface 51b, a discharge port 55 and a bypass port 57.

The first surface 51a faces the first end 11A of the housing 11 through the discharge chamber 16. The second surface 51b is disposed on an opposite side to the first surface 51a. The second surface 51b faces the orbital spiral 49.

The discharge port 55 (a fixed scroll discharge port) is a hole formed to pass through the center of the end plate 51. The discharge port 55 extends in the direction of the axis O1. The discharge port 55 discharges the high-pressure fluid, the compression of which is completed by the scroll compressor main body 26, to the discharge chamber 16.

The bypass port 57 is a hole formed to pass through the end plate 51 located outside a position where the discharge port 55 is formed. The bypass port 57 removes a medium compression fluid (which may be referred to as "low or medium pressure fluid" hereinafter), having a lower pressure than the high pressure fluid discharged from the discharge port 55, from an interior of the main body 26 of the scroll compressor.

The fixed shell 53 is provided on the second surface 51b of the end plate 51. The fixed shell 53 is erected in the direction of the O1 axis. The fixed shell 53 is a wall formed in a spiral shape when viewed in the direction of the O1 axis. The fixed shell 53 is formed, for example, by a plate-shaped member that is wound around the center of the end plate 51.

The orbital scroll 49 is disposed between the fixed scroll 48 and the main bearing 21. The orbital scroll 49 has an end plate 61, an orbital shell 62, a boss portion 64, and a bearing 66.

The end plate 61 is a disk-shaped plate and has a first surface 61a and a second surface 61b.

The first surface 61a is arranged to face the second surface 51b of the end plate 51. The second surface 61b is a surface provided on an opposite side to the first surface 61a.

The orbital envelope 62 is provided on the first surface 61a of the end plate 61. The orbital envelope 62 is erected in the direction of the O1 axis. The orbital envelope 62 is a wall formed in a spiral shape when viewed in the direction of the O1 axis. The orbital envelope 62 is formed, for example, by a plate-shaped member that is wound around the center of the end plate 61.

The orbital shell 62 having the above constitution is arranged to mesh with the fixed shell 53 described above. Thus, a compression chamber 26A, which is a space for compressing a fluid, is divided between the orbital shell 62 and the fixed shell 53. The orbital shell 62 is orbited relative to the fixed spiral 48, and thereby, the volume of the compression chamber 26A is changed. Thus, the fluid in the compression chamber 26A is compressed.

The projection portion 64 is provided at the center of the second surface 61b of the end plate 61. The projection portion 64 is a cylindrical member and protrudes in a direction from the second surface 61b of the end plate 61 to the sub-bearing 22. The projection portion 64 is arranged to surround an outer circumference of the eccentric shaft 46.

The bearing 66 is provided on an outer circumferential surface of the boss portion 64. A lubricant is supplied from the oil feed pump 24 to the bearing 66.

The bushing assembly 28 is provided between the orbital scroll 49 and the rotating shaft 23. The bushing assembly 28 couples the orbital scroll 49 and the rotating shaft 23. The bushing assembly 28 has a bushing 28A provided between the eccentric shaft 46 and the boss portion 64.

The Oldham ring 31 is provided between the orbital scroll 49 and the main bearing 21. The Oldham ring 31 has a lug fitted into a slot formed in the end plate 61 of the orbital scroll 49. The Oldham ring 31 is a member for inhibiting rotation of the orbital scroll 49 (which rotates about the eccentric axis O2).

Next, the first check valve 32 and the third check valve 33 will be described in turn with reference to Figs. 1 and 2. In Fig. 2, a state in which the first check valve 32 and the third check valve 33 are closed is schematically shown.

The first check valve 32 is a valve for controlling a backflow of the fluid from the side of the first surface 51a of the end plate 51. The first check valve 32 has a valve main body 71, a valve stroke adjusting member 72 and a bolt 73.

The valve main body 71 is a plate-shaped member. The valve main body 71 is arranged on the first surface 51a of the end plate 51 to block an outlet side of the bypass port 57. A first end of the valve main body 71 is fixed to the end plate 51 by the bolt 73.

The valve stroke adjusting member 72 is a plate-shaped member for setting a maximum valve stroke of the valve main body 71. The valve stroke adjusting member 72 has higher rigidity than the valve main body 71. The valve stroke adjusting member 72 is arranged on the valve main body 71. A first end of the valve stroke adjusting member 72 is fixed to the end plate 51 through the valve main body 71 by the bolt 73.

When a pressure in the bypass port 57 is higher than a pressure of an intermediate chamber 81 (near the first surface 51a of the end plate 51), the valve main body 71 is opened, and the first check valve 32 having the above constitution discharges the low- or medium-pressure fluid (the fluid having a lower pressure than the high-pressure fluid discharged from the discharge port 55) to the intermediate chamber 81 through the bypass port 57.

The third check valve 33 has a valve main body 75, a valve stroke adjusting member 76 and a bolt 77 which have the same constitution as the valve main body 71, the valve stroke adjusting member 72 and the bolt 73 described above.

The third check valve 33 is different from the first check valve 32 in that the valve main body 75 is arranged on the first surface 51a of the end plate 51 to block an outlet side of the discharge port 55.

In the third check valve 33 having the above constitution, when a pressure at the discharge port 55 is greater than a pressure at the first surface 51a side of the end plate 51, the valve main body 75 is opened and the high-pressure fluid is discharged to the first surface 51a side of the end plate 51.

The cover 35 will be described with reference to Figures 1 to 3. In Figure 3, a state in which the second check valve 42 is closed is schematically shown.

The cover 35 is provided in the discharge chamber 16 to face the first surface 51a of the end plate 51. An outer circumferential portion of the cover 35 is fixed to the casing 11.

The cover 35 is a member formed in an annular shape surrounding a portion located outside the discharge port 55 within the first surface 51a of the end plate 51 (to be specific, a portion in which the bypass port 57 and the first check valve 32 are formed). The cover 35 defines the annular intermediate chamber 81 together with the first surface 51a of the end plate 51. The intermediate chamber 81 is provided between the scroll compressor main body 26 and the discharge chamber 16 and outside the discharge port 55. The medium compression fluid is discharged from the bypass port 57 to the intermediate chamber 81.

In this way, the cover 35 is provided to surround the portion located outside the discharge port 55 within the first surface 51a of the end plate 51, and therefore, a region in which an outlet of the discharge port 55 is formed and a region in which an outlet of each of the bypass port 57 is formed can be separated from each other.

In this way, the high-pressure fluid discharged from the discharge port 55 and the low- or medium-pressure fluid discharged from the bypass port 57 can be prevented from mixing.

The cover 35 defines the annular intermediate chamber 81 together with the first surface 51a of the end plate 51, and therefore, the bypass port 57 can be provided at a desired position in a circumferential direction of the fixed spiral 48. In this way, a degree of freedom can be improved at a position where the bypass port 57 is formed.

The cover 35 has an opening 83 and a discharge port 85 (an intermediate chamber discharge port). The opening 83 is provided in the center of the cover 35 and exposes the third check valve 33. The opening 83 communicates with the discharge chamber 16.

When the third check valve 33 is opened, the high-pressure fluid in the scroll compressor main body 26 is discharged to the discharge chamber 16 through the opening 83.

The discharge port 85 is provided to pass through the cover 35. The discharge port 85 is a hole for spatially connecting the discharge chamber 16 and the intermediate chamber 81. The discharge port 85 has the function of inhibiting excessive compression loss.

The opening/closing of the discharge port 85 is controlled by the second check valve 42. When the first check valve 32 and the second check valve 42 are opened, the discharge port 85 discharges the low or medium pressure fluid, which is drawn from the bypass port 57, to the discharge chamber 16.

As described above, the bypass port 57 is provided in the end plate 51 of the fixed coil 48, and the discharge port 85 is provided in the cover 35 which is a different member of the fixed coil 48. In this way, the position at which the bypass port 57 is formed and a position at which the discharge port 85 is formed do not interfere with each other. Thus, the degree of freedom at the position at which the bypass port 57 is formed and the degree of freedom at the position at which the discharge port 85 is formed can be improved.

The discharge port 85 may be provided at a position where it is arranged opposite to the discharge pipe 14 in a direction in which the casing 11 extends (the direction of the O1 axis).

When the discharge port 85 is provided in this position, the pressure loss can be reduced.

In the bypass pipe 37, a portion located at a tip side thereof passes through the first end 11A of the casing 11 and the cover 35. A first end 37A of the bypass pipe 37 is disposed in the intermediate chamber 81.

Thus, the bypass pipe 37 is configured to be able to draw a fluid, which is discharged from the bypass port 57 to the intermediate chamber 81, to the outside of the intermediate chamber 81.

The remainder of the bypass pipe 37 is disposed outside the housing 11. The remainder of the bypass pipe 37 includes the second end 37B. The second end 37B is connected to the center of the housing 11. The second end 37B communicates with the suction chamber 17 in the housing 11.

The on/off valve 38 is provided for the bypass pipe 37 disposed outside the casing 11. The on/off valve 38 is turned to be open when the fluid capacity control operation is turned on, and thereby returns the medium compression fluid discharged to the intermediate chamber 81 to the suction chamber 17. For example, an electromagnetic valve may be used as the on/off valve 38.

When the first check valve 32 and the on/off valve 38 are opened, the low- or medium-pressure fluid discharged from the bypass port 57 returns to the suction chamber 17. Thus, a volume of the high-pressure fluid discharged from the discharge port 55 is reduced, and thus, a volume of the high-pressure fluid supplied from the scroll compressor 10 can be controlled.

The support member 39 is fixed to an outer side of the housing 11. The support member 39 supports the bypass pipe 37 and the on/off valve 38.

The second check valve 42 has a valve main body 91, a valve stroke adjusting member 92 and a bolt 93 which have the same constitution as the valve main body 71, the valve stroke adjusting member 72 and the bolt 73 described above.

The second check valve 42 is different from the first check valve 32 in that the valve main body 91 is arranged on the first surface 35a of the cover 35 to block an outlet side of the discharge port 85.

When the capacity control operation is turned on, the second check valve 42 opens when the pressure in the intermediate chamber 81 is greater than the pressure in the discharge chamber 16, and discharges the medium compression fluid, which is discharged to the intermediate chamber 81, to the discharge chamber 16 through the discharge port 85. Thereafter, the low or medium pressure fluid discharged to the discharge chamber 16 is discharged from the discharge pipe 14.

In this way, the low- or medium-pressure fluid discharged from the discharge port 85 flows through the discharge chamber 16 and then is guided into the discharge pipe 14. In this way, the fluid pulsation can be reduced in the discharge chamber 16. In this way, the occurrence of fluid pulsation can be inhibited.

In this document, with reference to Fig. 4, a fluid capacity control operation (an operation when the fluid capacity control operation is turned on) and a fluid full load operation (operation when the fluid capacity control operation is turned off) will be described in the scroll compressor shown in Fig. 1. In Fig. 4, the same constituent portions as those of the structure shown in Figs. 1 to 3 are given the same reference numerals.

First, a case will be described in which the on/off valve 38 is opened to perform the capacity control operation. In this case, a pressure of the intermediate chamber 81 becomes equal to that of the suction chamber 17. Thus, the pressure of the intermediate chamber 81 becomes lower than that of the discharge chamber 16. Accordingly, the second check valve 42 remains closed. That is, even when the first check valve 32 is opened, the low- or medium-pressure fluid is not discharged from the intermediate chamber 81 to the discharge chamber 16.

On the other hand, a case will be described in which the on/off valve 38 is closed to perform the full-load operation. In this case, since the intermediate chamber 81 is in a state of not communicating with the suction chamber 17, a pressure of the intermediate chamber 81 becomes higher than that of the suction chamber 17. When the pressure of the intermediate chamber 81 becomes higher than that of the discharge chamber 16, the second check valve 42 is opened. Accordingly, the first check valve 32 is opened, and the low- or medium-pressure fluid discharged to the intermediate chamber 81 is discharged to the discharge chamber 16 through the intermediate chamber 81, and thus, excessive compression loss can be inhibited.

In the scroll compressor 10, for example, when an opening area of the bypass port 57 is defined as Sv, an opening area of the discharge port 85 is defined as Sm, an opening area of the discharge port 55 is defined as St and an opening area of the discharge pipe 14 is defined as Sf, the following formula (2) can be satisfied.

Sv<Sm<St<Sf................... (2)

In this way, Sv, Sm, St and Sf are set to satisfy formula (2) and thus the pressure loss can be reduced.

In the scroll compressor 10, for example, the third check valve 33 may be configured to be lifted with a harder time than the first check valve 32 and the second check valve 42, and the second check valve 42 may be configured to be lifted with a harder time than the first check valve 32. With this constitution, the pressure loss can be reduced.

According to the scroll compressor 10 of the first embodiment, the discharge chamber 16 communicating with the discharge pipe 14 is provided. Thus, since the fluid discharged from the discharge port 85 flows through the discharge chamber 16 and then is guided into the discharge pipe 14, the fluid pulsation can be reduced in the discharge chamber 16. Thus, the occurrence of fluid pulsation can be inhibited.

The bypass port 57 is provided on the end plate 51 of the fixed spiral 48, and the discharge port 85 is provided on the cover 35 which is the different member of the fixed spiral 48, and therefore, the position at which the bypass port 57 is formed and the position at which the discharge port 85 is formed do not interfere with each other. For this reason, the degree of freedom for the position at which the bypass port 57 is formed and the degree of freedom for the position at which the discharge port 85 is formed can be improved.

(Second realization)

A scroll compressor 100 of a second embodiment of the present invention will be described with reference to Fig. 5. In Fig. 5, the same constituent portions as those of the structure shown in Figs. 1 to 4 are given the same reference numerals.

In Fig. 5, a case where two bypass ports 57 and two first check valves 32 are provided will be described by way of example. However, the number of bypass ports 57 and the number of first check valves 32 only need to be multiple and are not limited to two.

Referring to Fig. 5, the scroll compressor 100 has a structure in which a scroll compressor main body 26 has two compression chambers 26A. The scroll compressor 100 has the same constitution as the scroll compressor 10 of the first embodiment, except that the bypass port 57 and the first check valve 32 are provided in each of the compression chambers 26A.

That is, the scroll compressor 100 has the two bypass ports 57 and the first two check valves 32. The two bypass ports 57 and the first two check valves 32 are arranged in an intermediate chamber 81.

The two bypass ports are arranged in a circumferential direction of an end plate 51 of a fixed spiral 48. The two bypass ports 57 may be arranged, for example, to face each other through an axis O1.

According to the scroll compressor 100 of the second embodiment, the plurality of bypass ports 57 and the plurality of first check valves 32 are arranged in the intermediate chamber 81, and therefore, a fluid can be discharged from the plurality of bypass ports 57 to the intermediate chamber 81.

In this way, since the fluid discharged from the plurality of bypass ports 57 can be guided to a discharge pipe 14 through a discharge port 85, the constitution of the scroll compressor 100 can be simplified.

Although the preferred embodiments of the present invention have been described in detail, the present invention is not limited to the specified embodiments, and various modifications and alterations are possible without departing from the scope of the present invention described in the claims.

In the first and second embodiments, as examples of the scroll compressors 10 and 100, the case where the cover 35 is provided and the second check valve 42 is provided for the cover 35 has been described by way of example. However, the second check valve 42 may be configured to be embedded in the end plate 51 without providing the cover 35. In this case, the same effects as in the scroll compressor 10 of the first embodiment can be obtained.

EXPLANATION OF REFERENCES

10, 100 Scroll compressor

11 Housing

IIA , 37A, 45A First end

IIB, 37B, 45B Second end

12 Suction pipe

14 Discharge pipe

16 Discharge chamber

17 Suction chamber

21 Main bearing

22 Sub bearing

23 Rotary shaft

24 Oil feed pump

25 Actuator

26 Main body of scroll compressor

26A Compression chamber

28 Bushing assembly

28A Socket

31 Oldham Ring

32 First check valve

33 Third check valve

35 Cover

35a, 51a, 61a First surface

37 Bypass pipe

38 On/Off Valve

39 Support Member

42 Second return valve

45 Main body of rotating shaft

46 Eccentric tree

48 Fixed spiral

49 Orbital spiral

51, 61 End Plate

51b, 61b Second surface

53 Fixed wrap

55 Discharge port

57 Bypass port

62 Orbital envelope

64 Part of overhang

66 Bearing

71, 75, 91 Main valve body

72, 76, 92 Valve travel adjustment member

73, 77, 93 Bolt

81 Intermediate chamber

83 Opening

85 Discharge port

01 Axis

02 Eccentric shaft

Claims (6)

1. A scroll compressor (10, 100) comprising: a suction chamber (17) into which a fluid is introduced; a discharge chamber (16) configured to communicate with a discharge pipe (14); a scroll compressor main body (26) having a fixed scroll (48) and an orbital scroll (49) provided between the suction chamber and the discharge chamber and configured to discharge the fluid to be compressed from a discharge port (55), which is provided on the fixed scroll, to the discharge chamber; a bypass port (57) configured to remove a medium compression fluid from the scroll compressor main body located outside the discharge port; an intermediate chamber (81) provided between the scroll compressor main body and the discharge chamber and outside the discharge port; a first check valve (32) configured to discharge the medium compression fluid to the intermediate chamber through the bypass port; an on/off valve (38) configured to return the medium compression fluid, which is discharged to the intermediate chamber, to the suction chamber when the on/off valve is opened; and a second check valve (42) configured to open when the pressure in the intermediate chamber becomes higher than the pressure in the discharge chamber, and to discharge the medium compression fluid, which is discharged to the intermediate chamber, to the discharge chamber through the intermediate chamber discharge port (85) when the on/off valve is closed, The first check valve (32) is provided on a first surface (51a) of an end plate (51) of the fixed scroll (48) located on the discharge chamber side of the fixed scroll, The scroll compressor further comprises a cover (35) provided to face the first surface (51a) of the end plate (51) and configured to define the intermediate chamber (81) together with the end plate of the fixed scroll, characterized by that The scroll compressor (10, 100) further comprises: a bypass pipe (37) configured to guide the medium compression fluid, which is withdrawn from the bypass port (57), to the suction chamber, wherein the on/off valve (38) is provided for the bypass pipe and a casing (11) in which the main body (26) of the scroll compressor and the cover (35) are housed, and which defines the discharge chamber (16) together with the cover, wherein the discharge pipe (14) is provided so that the housing (11) communicates with the discharge chamber (16), and The on/off valve (38) is arranged outside the housing, wherein the intermediate chamber discharge port (85) and the second check valve (42) are provided for the cover (35), The cover (35) is provided with an opening (83) configured to communicate the discharge port (55) and the discharge chamber (16), and The medium compression fluid is compressed to have a lower pressure than the fluid discharged from the discharge port (55). 2. The scroll compressor according to claim 1, wherein the cover (35) is a member formed in an annular shape surrounding a portion located outside the discharge port (55) within the first surface (51a) of the end plate (51). 3. The scroll compressor according to any one of claims 1 to 2, comprising a plurality of bypass ports (57) provided in a circumferential direction of the fixed spiral (48); and The first check valve (32) is provided for each of the plurality of bypass ports. 4. The scroll compressor according to any one of claims 1 to 3, wherein, when an opening area of the bypass port (57) is defined as Sv, an opening area of the intermediate chamber discharge port (85) is defined as Sm, an opening area of the discharge port (55) is defined as St, and an opening area of the discharge pipe (14) is defined as Sf, the following formula (1) is satisfied. Sv<Sm<St<Sf............. (1) 5. The scroll compressor according to any one of claims 1 to 4, further comprising a third check valve (33) provided to the first surface (51a) of the end plate (51) of the fixed scroll (48) and configured to open the discharge port (55) when the pressure in the discharge port is higher than a pressure of the discharge chamber, wherein the third check valve is configured to be lifted with more difficulty than the first check valve and the second check valve, and the second check valve is configured to be lifted with more difficulty than the first check valve. 6. The scroll compressor according to any one of claims 1 to 5, wherein the intermediate chamber discharge port (85) is arranged opposite to the discharge pipe (14) in an extension direction of the casing.