WO2016031278A1

WO2016031278A1 - Scroll fluid machine and refrigeration machine with same

Info

Publication number: WO2016031278A1
Application number: PCT/JP2015/057799
Authority: WO
Inventors: 尚史大谷; 戸部隆久; 康臣松本
Original assignee: サンデンホールディングス株式会社
Priority date: 2014-08-28
Filing date: 2015-03-17
Publication date: 2016-03-03
Also published as: DE112015003964T5; JP2016048056A

Abstract

The purpose of the present invention is to facilitate the starting of a scroll fluid machine (1) which is a single plate-type compression machine-integrated expansion machine in which the low-stage-side compression section of a refrigeration device is configured together with a high-stage-side compressor. A refrigerant compressed by the compression section (3) of the scroll fluid machine (1) is sucked into a high-stage-side compression machine, and the high-pressure refrigerant compressed by the high-pressure-side compression machine is sucked into an expansion section (2). The scroll fluid machine (1) is provided with: a back-pressure chamber (52) formed on the rear surface (7c) side of a movable scroll (7), which is on the reverse side of the base surface (7b) of the movable scroll (7); an oil return passage (47) for causing the back-pressure chamber (52) and the discharge side of the compression section to be in communication with each other; and a check valve device (66) provided in the oil return passage (47) and configured so that the direction leading from a compression-side discharge chamber (22), which is on the discharge side of the compression section, to a lubricating oil chamber (26), which is on the back-pressure chamber side, is the flow-permitted direction.

Description

Scroll type fluid machine and refrigeration apparatus using the same

The present invention relates to a scroll type fluid machine that forms an expansion chamber and a compression chamber of a working fluid between wraps of fixed and movable scrolls, and a refrigeration apparatus using the scroll type fluid machine.

This type of scroll type fluid machine includes a scroll unit including a movable scroll provided with a lap on the base surface and a fixed scroll provided with a wrap meshing with the lap of the movable scroll on the base surface. There is known a single plate type compressor-integrated expander in which a working chamber of a unit is divided into an expansion chamber and a compression chamber by a partition wall to form a central expansion portion and an outer compression portion (for example, Patent Document 1).

Also, a back pressure chamber is configured on the back side opposite to the base surface of the movable scroll. The back pressure chamber is supplied with a working fluid maintained at the discharge pressure of the compression section, and is urged so that the movable scroll is pressed against the fixed scroll by the pressure on the discharge side of the compression section.

Such a scroll type fluid machine is used, for example, in a heat pump for heating a hot water heater or the like, and constitutes a refrigeration cycle of a refrigeration apparatus together with a high-stage compressor, a radiator, and a heat absorber (evaporator). In this case, the working fluid compressed by the high-stage compressor flows into the radiator and radiates heat there. This working fluid is sucked into the expansion portion from the center portion of the fixed scroll of the scroll type fluid machine while being kept at a high pressure, and is expanded in an expansion chamber formed between the wraps of the expansion portion, whereby the movable scroll is revolved. Power is recovered.

The working fluid (refrigerant) that has exited the expansion part of the scroll type fluid machine flows into the heat absorber and evaporates. After exerting the endothermic action, the working fluid is sucked into the compression part from the outer peripheral part of the fixed scroll of the scroll type fluid machine. The working fluid sucked into the compression unit is compressed in the compression chamber formed between the wraps of the compression unit by the power recovered by the expansion unit. That is, the compression unit of the scroll type fluid machine is on the lower stage side, and the working fluid compressed by the lower stage compression unit is repeatedly circulated by being sucked into the higher stage compressor (for example, Patent Documents). 2).

In this case, as shown in FIG. 4 of Patent Document 2, the conventional refrigeration apparatus is provided with a bypass pipe that bypasses the suction side and the discharge side of the compression unit of the scroll type fluid machine. The bypass pipe is provided with an opening / closing valve. By opening the opening / closing valve only when the high-stage compressor is started, the low-stage compression section is bypassed. The purpose is to increase the discharge pressure of the high-stage compressor quickly and increase the power applied to the expansion part early by making the high-stage compressor easily suck the working fluid. It was intended to start the scroll fluid machine quickly.

Japanese Patent No. 5209964 Japanese Patent No. 3953871

As described above, in the conventional refrigeration apparatus, when the high-stage compressor is started, the suction side and the discharge side of the compression unit (low-stage compression unit) of the scroll type fluid machine are bypassed by the bypass pipe. It is considered that it is easier to start the scroll type fluid machine if the working fluid is sucked from the compression part of the scroll type fluid machine than when the high stage compressor is started without providing such a bypass pipe.

This is because when the working fluid is sucked in from the discharge side of the compression unit of the scroll type fluid machine by the high-stage compressor, the pressure on the discharge side of the compression unit of the scroll type fluid machine causes the suction of the compression unit. This is because the pressure difference is lower than the pressure side, and a starting torque is generated in the scroll type fluid machine in the direction of compressing the working fluid in the compression part of the scroll type fluid machine. That is, in addition to the power recovered in the expansion part, power is also generated in the compression part, and the scroll fluid machine is easily started.

However, since the scroll type fluid machine has a structure in which the pressure on the discharge side of the compression unit is supplied as the back pressure of the movable scroll as described above, and the movable scroll is pressed against the fixed scroll by this back pressure, the high-stage compressor If the pressure on the discharge side of the compression part of the scroll type fluid machine becomes lower than the suction side of the compression part at the time of starting, the back pressure of the movable scroll is surely insufficient.

Therefore, there is a problem that the movable scroll is pulled away from the fixed scroll, the above-described expansion chamber and compression chamber cannot be formed between the wraps, and the scroll type fluid machine becomes inoperable.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the conventional technical problem, and is a single plate type compressor-integrated expander that constitutes a low-stage compression section of a refrigeration apparatus together with a high-stage compressor. It is an object of the present invention to enable easy activation of the scroll type fluid machine.

In order to solve the above-mentioned problems, a scroll type fluid machine according to the present invention is composed of a fixed scroll and a movable scroll each having a spiral wrap formed on each base surface of each substrate so as to face each other. Formed between each lap of both scrolls by expanding the working fluid in the expansion chamber formed between them, revolving the revolving motion of the movable scroll to recover the power, and the power recovered by this expansion section And a low-stage compression section that compresses the working fluid in the compressed chamber, and the working fluid compressed by the compression section is sucked into the high-stage compressor and compressed by the high-stage compressor. The high-pressure working fluid is sucked into the expansion portion, and the back pressure chamber formed on the back side opposite to the base surface of the movable scroll is connected to the discharge side of the compression portion and the back pressure chamber. And a communication path to This provided the communication passage, the direction from the discharge side of the compression unit to the back pressure chamber side, characterized in that a forward and has been non-return valve device.

The scroll type fluid machine according to a second aspect of the invention is characterized in that, in the above invention, the check valve device includes a narrow passage communicating the back pressure chamber side and the discharge side of the compression portion.

According to a third aspect of the present invention, there is provided a scroll type fluid machine including a frame having a pedestal portion which supports the movable scroll so as to be capable of revolving orbiting at an outer peripheral portion of a rear surface of the movable scroll in each of the above inventions. The check valve device is formed of a reed valve attached to the frame so as to close the outlet on the back pressure chamber side of the communication path.

A scroll type fluid machine according to a fourth aspect of the present invention is characterized in that a small hole is formed in the reed valve in the above invention.

The scroll type fluid machine of the invention of claim 5 is characterized in that, in the invention of claim 3, a small groove is formed in the valve seat of the reed valve.

A refrigeration apparatus according to a sixth aspect of the invention comprises the scroll type fluid machine according to any one of the first to fifth aspects and a high-stage compressor, and the compression of the scroll type fluid machine. The working fluid is sucked into the higher stage compressor than the discharge side of the part, the high pressure working fluid compressed by the higher stage compressor is sucked into the expansion part of the scroll type fluid machine, and the higher stage side The working fluid is sucked from the compression portion of the scroll type fluid machine from the start of the compressor.

The refrigeration apparatus of the invention of claim 7 is characterized in that carbon dioxide is used as the working fluid in the above invention.

The present invention is composed of a fixed scroll and a movable scroll in which spiral wraps are formed on each base surface of each substrate so as to face each other, and a working fluid is expanded in an expansion chamber formed between the wraps of both scrolls. The low-stage side that compresses the working fluid in the compression chamber formed between the laps of the two scrolls by the expansion portion that revolves the orbiting scroll to recover the power and the power recovered by the expansion portion A scroll type in which the working fluid compressed by the compression unit is sucked into the high-stage compressor, and the high-pressure working fluid compressed by the high-stage compressor is sucked into the expansion unit In a fluid machine, a back pressure chamber formed on the back side opposite to the base surface of the movable scroll, a communication path for communicating the discharge side of the compression unit and the back pressure chamber, and a communication path provided in the communication path Of the compression part And a check valve device in which the direction from the outlet side toward the back pressure chamber side is a forward direction. Thus, the compressor of the scroll type fluid machine is compressed at a higher stage than the discharge side. The scroll type fluid machine of the present invention is used in a refrigeration apparatus that sucks the working fluid into the machine and sucks the high pressure working fluid compressed by the high stage side compressor into the expansion part of the scroll type fluid machine, and Even when the working fluid is sucked from the compressor of the scroll type fluid machine from the time of starting the high stage side compressor, the scroll type fluid machine is used at the time of starting the high stage side compressor by the check valve device. The inconvenience that the pressure in the back pressure chamber is suddenly reduced is prevented.

As a result, the movable scroll is fixed even if the working fluid is sucked from the compression unit of the scroll type fluid machine from the start of the high-stage compressor without bypassing the compression unit of the scroll type fluid machine as in the prior art. The scroll type fluid machine can be activated without being peeled off from the scroll and pressed against the fixed scroll. Then, by sucking the working fluid from the discharge side of the compression unit with the high-stage compressor, the pressure on the discharge side of the compression unit becomes lower than the pressure on the suction side of the compression unit. Thereby, since a starting torque is generated in the scroll type fluid machine, it is possible to start up more easily than in the prior art.

In this case, the check valve device is provided with a narrow passage that communicates the back pressure chamber side and the discharge side of the compression portion as in the invention of claim 2 so that the check valve device is activated after the high-stage compressor is started. The pressure gradually passes through the narrow passage to the discharge side of the compression section. That is, the pressure in the back pressure chamber that has risen to an equilibrium pressure higher than the pressure on the discharge side of the compressor during the stop is gradually reduced after the high-stage compressor is started. As a result, the pressure in the back pressure chamber can be lowered to the pressure on the discharge side of the compression unit early after the scroll type fluid machine is started, and the back pressure applied to the movable scroll can be quickly set to an appropriate value. It becomes like this.

According to a third aspect of the present invention, there is provided a frame having a pedestal portion that supports the movable scroll so as to be capable of revolving orbiting at the outer peripheral portion of the rear surface of the movable scroll, and the communication passage is formed in the frame, and the check valve device By using a reed valve attached to the frame so as to close the outlet on the back pressure chamber side of the communication path, the communication path and the check valve device can be realized with a simple configuration, and the structure can be simplified. It becomes possible.

Further, a small hole is formed in the reed valve as in the invention of claim 4, or a small groove is formed in the valve seat of the reed valve as in the invention of claim 5, whereby the narrow passage of claim 2 is simply configured. Can be realized.

The above inventions are particularly effective for a refrigeration apparatus using carbon dioxide as a working fluid as in the invention of claim 7.

It is a vertical side view of the scroll type fluid machine of one example to which the present invention is applied. It is the top view which looked at the fixed scroll of FIG. 1 from the base surface side. FIG. 3 is a sectional view taken along line AA in FIG. 2. It is an expanded sectional view of the check valve device part of the scroll type fluid machine of FIG. It is a figure which shows the refrigerating cycle of the freezing apparatus of one Example using the scroll type fluid machine of FIG. It is a figure explaining the change of the pressure of each part of the scroll type fluid machine of FIG.

Hereinafter, embodiments of the present invention will be described in detail.

(1) Basic Structure of Scroll Type Fluid Machine 1 FIG. 1 shows a vertical side view of a scroll type fluid machine 1 according to an embodiment of the present invention. The scroll type fluid machine 1 of the embodiment is, for example, a vertically installed single-plate type compressor-integrated expander, and refrigeration of a refrigeration apparatus RC that uses carbon dioxide whose high pressure side is a supercritical pressure as a refrigerant (working fluid). Used in the cycle (FIG. 5). Although the configuration of the refrigeration apparatus RC will be described in detail later, the refrigeration apparatus RC is incorporated as a heat pump in an air conditioner, a heat pump hot water heater, or the like (not shown). The scroll fluid machine 1 according to the embodiment includes an expansion unit 2 that performs an expansion operation by the pressure of the refrigerant, and a compression unit 3 (low stage side) that performs a compression operation by the expansion operation of the expansion unit 2 ( Figure 2).

The scroll fluid machine 1 includes a housing 4. In the housing 4, a scroll unit 8 mainly composed of a fixed scroll 6 and a movable scroll 7 that revolves with respect to the fixed scroll 6, and a frame that supports the movable scroll 7 so that it can revolve. A main frame 9 and a fixed shaft 11 fixed to the bottom surface of the main frame 9 and protruding from the bottom surface of the main frame 9 are disposed.

The housing 4 includes a main shell 12 serving as a main body, a cap-shaped top shell 13 that covers the upper portion of the main shell 12, and a cap-shaped bottom shell 14 that covers the lower portion of the main shell 12. The housing 4 is assembled by fastening the top shell 13 and the bottom shell 14 together with bolts so as to sandwich the main shell 12 via a sealing material such as an O-ring, and the inside is sealed from the outside. The outer periphery of the main frame 9 is fixed inside the main shell 12. In the sealed housing 4, a pressure obtained by compressing the refrigerant (carbon dioxide) taken in from the refrigeration cycle of the refrigeration apparatus RC as the working fluid of the scroll type fluid machine 1 by the compression unit 3 acts.

The top shell 13 is connected to an expansion side suction pipe 16 that sucks refrigerant taken from the refrigeration cycle of the refrigeration apparatus RC into the expansion section 2. The main shell 12 includes an expansion side discharge pipe 17 that discharges the refrigerant expanded in the expansion unit 2 toward the refrigeration cycle of the refrigeration apparatus RC, and the refrigerant compressed in the compression unit 3 in the refrigeration cycle of the refrigeration apparatus RC. A compression-side discharge pipe 18 that discharges toward is connected. The ends of the expansion side suction pipe 16 and the expansion side discharge pipe 17 are opened and communicated with an expansion side suction chamber 19 and an expansion side discharge chamber 21 formed in the substrate 6 a of the fixed scroll 6, respectively. An end portion of the pipe 18 opens into the main shell 12 and communicates with a compression side discharge chamber 22 as a discharge side of the compression portion 3 formed inside the top shell 13 through the main shell 12.

Further, the main shell 12 is connected to a compression side suction pipe 23 (shown in FIG. 3, which is located on the front side in FIG. 1) that sucks the refrigerant taken from the refrigeration cycle of the refrigeration apparatus RC into the compression unit 3. An end portion of the compression side suction pipe 23 is communicated with a compression side suction chamber 24 as a suction side of the compression portion formed in the substrate 6 a of the fixed scroll 6.

Meanwhile, a lubricating oil chamber 26 is formed inside the bottom shell 14, and lubricating oil for lubricating the scroll unit 8 is stored in the lubricating oil chamber 26. The compression side suction chamber 23 is provided with an oil feed hole 27 (FIG. 2) penetrating the substrate 6 a and the main frame 9 of the fixed scroll 6, and the lubricating oil chamber 26 is formed through the oil feed hole 27. The lubricating oil is supplied to the compression side suction chamber 24.

Further, an oil supply passage 28 is formed in the fixed shaft 11 along the axial direction of the fixed shaft 11. The lower end of the oil supply passage 28 opens into the lubricating oil chamber 26, and the upper end is a boss (concave portion) 31. It is opened in the inner space.

The fixed scroll 6 is fixed to the upper surface portion 9 a of the main frame 9, and the compression side discharge hole 32 penetrates slightly in the center in the radial direction of the fixed scroll 6 with respect to the compression side suction chamber 24 of the substrate 6 a of the fixed scroll 6. Is formed. An oil separator 33 for separating the lubricating oil in the refrigerant is attached to the opening of the compression side discharge hole 32 with respect to the compression side discharge chamber 22.

The movable scroll 7 is supported by the outer peripheral portion of the back surface 7c on the pedestal portion 9b of the main frame 9 so as to be capable of revolving without rotating through a rotation prevention mechanism 34 such as an Oldham ring. This rotation prevention mechanism 34 is inserted into the pedestal portion 9b, and is slidably connected to the back surface 7c, which is the surface opposite to the base surface 7b of the substrate 7a, along with the revolving turning motion of the movable scroll 7. Further, on the back surface 7c of the movable scroll 7, the above-described cylindrical boss 31 into which the eccentric bush 36 is slidably and rotatably fitted is projected.

The fixed shaft 11 described above constitutes a support mechanism 54 that supports the movable scroll 7 together with the main frame 9 so as to be capable of revolving and turning at the center of the back surface 7c. In this case, the upper end portion of the fixed shaft 11 is inserted inside the slide bush 56 so as to be slidable and rotatable by a bearing 49. The slide bush 56 is accommodated in the eccentric bush 36 so as to be movable in the eccentric direction. Has been. That is, the upper end portion of the fixed shaft 11 is inserted into the eccentric bush 36 via the slide bush 56. A spring 61 is interposed between the slide bush 56 and the eccentric bush 36. The slide bush 56 is constantly urged in the eccentric direction by the spring 61, and thereby the misalignment of the

scrolls

6 and 7 is adjusted.

The eccentric bush 36 is inserted into the boss 31 via a bearing 48 so as to be slidable and rotatable. The bearing 48 receives a radial load that acts on the eccentric bush 36 as the orbiting scroll 7 revolves. Further, a bearing 51 is disposed between the lower end of the eccentric bush 36 and the main frame 9. As described above, the fixed shaft 11 supports the movable scroll 7 through the bearing 49, the slide bush 56, the eccentric bush 36, the bearing 48, and the bearing 51 so as to be capable of revolving, and the support mechanism 54 includes the boss 31, The eccentric bush 36, the slide bush 56, the fixed shaft 11, and the spring 61 are configured.

Here, the scroll unit 8 of the embodiment is a compressor-integrated expander, and includes a compression chamber of the compression unit 3 and an expansion chamber of the expansion unit 2 as a refrigerant working chamber by a pair of fixed scroll 6 and movable scroll 7. The fixed shaft 11 only supports the movable scroll 7 together with the main frame 9 so as to be capable of revolving, and the fixed shaft 11 itself is driven to rotate. There is no.

In detail, as shown in FIG. 2, an annular intermediate partition wall (annular wall) 38 and an annular outer partition wall 39 are erected on the base surface 6 b of the fixed scroll 6. A spiral outer fixed scroll wrap (wrap) 40 is provided between the partition wall (annular wall) 39 and a spiral inner fixed scroll wrap (wrap) 41 is provided on the center side of the intermediate partition wall 38. ing. Further, an annular groove 42 into which a seal ring (not shown) is inserted is recessed in the end surface of the intermediate partition wall 38 on the base surface 6b. By the seal ring of the annular groove 42, the inside of the scroll unit 8 is partitioned into an inner expansion portion 2 side and an outer compression portion 3 side.

On the substrate 6 a of the fixed scroll 6, the above-described compression side suction chamber 24 is formed at the outer peripheral end of the compression portion 3 slightly inside the outer partition wall 39, and the inner peripheral end of the compression portion 3 slightly outside the intermediate partition wall 38. A compression-side discharge hole 32 is formed in the upper part. In addition, the expansion side discharge chamber 21 described above is formed on the outer peripheral end of the expansion portion 2 slightly inside the intermediate partition wall 38 on the substrate 6a, and the expansion side suction chamber 19 described above is the inner peripheral end of the expansion portion 2. It is formed at the center. Furthermore, an annular oil groove 43 is formed on the substrate 6a slightly outside the outer partition wall 39, and is countersunk at a predetermined depth with a diameter larger than the groove width provided on the oil groove 43. The oil feed hole 27 described above is formed on the bottom surface of the formed recess.

On the other hand, on the base surface 7 b of the movable scroll 7, a spiral outer movable scroll wrap (wrap) 44 that meshes with the outer fixed scroll wrap 40 and a spiral inner movable scroll wrap (wrap) that meshes with the inner fixed scroll wrap 41. ) 46 is erected in the direction of the opposite spiral.

According to the scroll unit 8 described above, the expansion part 2 is formed inside the intermediate partition wall 38, and the compression part 3 is formed between the intermediate partition wall 38 and the outer partition wall 39. Specifically, as indicated by solid line arrows in FIG. 1, the refrigerant sucked from the expansion side suction pipe 16 is taken into the central portion of the expansion portion 2 through the expansion side suction chamber 19, and the

scrolls

6, 7 are mutually connected. By cooperating, it is expanded in an expansion chamber (working chamber) formed between the

laps

41 and 46. The volume of the expansion chamber is increased while moving toward the outer peripheral side of each of the

scrolls

6, 7, and accordingly, the movable scroll 7 is revolved around the axis of the fixed scroll 6. The refrigerant used for the revolving orbiting motion of the movable scroll 7 is discharged toward the refrigeration cycle of the refrigeration apparatus RC outside the housing 4 through the expansion side discharge chamber 21 via the expansion side discharge chamber 21.

On the other hand, the refrigerant sucked from the compression side suction pipe 23 is taken into the compression section 3 through the compression side suction chamber 24, and the movable scroll 7 moves around the axis of the fixed scroll 6 along with the expansion of the refrigerant in the expansion chamber described above. , The

scrolls

6 and 7 are compressed in a compression chamber (working chamber) formed between the

laps

40 and 44 by cooperating with each other. The volume of the compression chamber is reduced while moving toward the center of each of the

scrolls

6 and 7 as the orbiting scroll 7 revolves. As the volume of the compression chamber decreases, the high-pressure refrigerant passes through the compression-side discharge hole 32 and the compression-side discharge chamber 22 and then passes through the compression-side discharge pipe 18 toward the refrigeration cycle of the refrigeration apparatus RC outside the housing 4. Discharged.

(2) Oil return path (communication path) 47
Further, in this process, as indicated by a dotted arrow in FIG. 1, the refrigerant discharged from the compression-side discharge hole 32 to the compression-side discharge chamber 22 causes the lubricating oil in the refrigerant to pass through the oil separator 33. To be separated. The lubricating oil separated from the refrigerant is an oil return passage 47 as a communication passage for communicating the discharge side (compression side discharge chamber 22) of the compression section 3 formed in the main frame 9 and the back pressure chamber 52 with each other. Then, the oil is stored in the lubricating oil chamber 26.

The lubricating oil stored in the lubricating oil chamber 26 rises in the oil supply passage 28 due to the differential pressure between the lubricating oil chamber 26 and the back pressure chamber 52, is discharged from the upper end of the fixed shaft 11, and has a bearing 49, a bearing 48, and a bearing 51. After being lubricated, the pressure reaches the back pressure chamber 52 formed between the pedestal 9b of the main frame 9 and the back surface 7c of the movable scroll 7.

(3) Back pressure of movable scroll 7 As described above, in the back pressure chamber 52 of the scroll type fluid machine 1, a sliding portion between the rotation prevention mechanism 34 and the base portion 9b and the back surface 7c of the movable scroll 7 is caused by the lubricating oil. Lubricated. Further, since the inside of the housing 4 is maintained at the discharge pressure of the compression section 3 discharged from the compression side discharge hole 32 to the compression side discharge chamber 22, it passes through the oil return passage 47, the lubricating oil chamber 26, and the oil supply passage 28. The back pressure chamber 52 is supplied with a refrigerant (working fluid) maintained at the discharge pressure of the compression unit 3 together with the lubricating oil. Accordingly, the movable scroll 7 from the back pressure chamber 52 is pressed and urged against the fixed scroll 6 by the discharge pressure of the compression unit 3.

Due to the pressure (back pressure) from the back pressure chamber 52, the tips of the

wraps

44 and 46 of the movable scroll 7 abut against the base surface 6 b of the fixed scroll 6, and the tips of the

wraps

40 and 41 of the fixed scroll 6 are the movable scroll 7. The base surface 7b of each other (both contact with the lubricating oil). As a result, an expansion chamber is formed in the expansion portion 2 between the laps, and a smooth revolving motion of the movable scroll 7 with respect to the fixed scroll 6 is possible while forming a compression chamber in the compression portion 3. In the scroll type fluid machine 1, the scroll unit 8 is driven by the expansion energy of the refrigerant in the expansion unit 2, and the refrigerant is compressed in the compression unit 3 by the driving force of the scroll unit 8.

(4) Check valve device 66
A check valve device 66 is attached to the lower surface of the main frame 9. The check valve device 66 of this embodiment includes a reed valve 67 and a bolt 68 that fixes the reed valve 67 to the main frame 9. The reed valve 67 is the back pressure chamber 56 of the oil return passage 47. It arrange | positions so that the exit used as a side may be plugged up (FIG. 4).

In this case, the outlet of the oil return passage 47 is also opened on the lower surface of the main frame 9, and a valve seat 47a of the reed valve 67 projects from the periphery of the outlet as shown in FIG. The reed valve 67 abuts on the valve seat 47 a to close the outlet of the oil return path 47. The reed valve 67 corresponding to the outlet of the oil return passage 47 is provided with a small hole 67a for forming a narrow passage (FIG. 4).

The reed valve 67 of the check valve device 66 has a forward direction from the compression side discharge chamber 22 on the discharge side of the compression unit 3 toward the lubricating oil chamber 26 on the back pressure chamber 52 side, and the compression side discharge chamber. The passage of the lubricating oil in the direction from 22 to the lubricating oil chamber 26 is allowed, and the movement of the lubricating oil in the opposite direction is such that the reed valve 67 contacts the valve seat 47a and closes the outlet of the oil return passage 47. It is configured to be blocked by.

That is, when the pressure in the compression side discharge chamber 22 (pressure on the discharge side of the compression unit 3) is equal to or higher than the pressure (back pressure) in the back pressure chamber 52 communicating with the lubricating oil chamber 26 via the oil supply passage 28. The reed valve 67 of the check valve device 66 is spaced from the valve seat 47a to open the outlet of the oil return passage 47, and allows the lubricating oil from the compression side discharge chamber 22 to the lubricating oil chamber 26 on the back pressure chamber 52 side to pass therethrough.

On the other hand, when the pressure in the compression side discharge chamber 22 becomes lower than the pressure in the back pressure chamber 52 (pressure in the lubricating oil chamber 26), the reed valve 67 contacts the valve seat 47a and closes the outlet of the oil return passage 47. . However, since the small hole 67a is formed in the reed valve 67, even when the reed valve 67 closes the outlet of the oil return passage 47, the discharge from the lubricating oil chamber 26 (on the back pressure chamber 52 side) is discharged. A very small amount of lubricating oil (pressure) is allowed to move to the chamber 22 (the discharge side of the compression unit 3).

(5) Refrigeration equipment RC
Next, FIG. 5 shows a refrigeration cycle of the refrigeration apparatus RC of one embodiment using the scroll type fluid machine 1 of the present invention. In this figure, for the sake of explanation, the expansion portion 2 and the compression portion 3 of the scroll type fluid machine 1 are shown separately. The compression unit 3 driven by the power recovered by the expansion unit 2 of the scroll type fluid machine 1 constitutes a low-stage compressor (low-stage compression unit) in the refrigeration cycle of the refrigeration apparatus RC. The above-described compression-side discharge pipe 18 of the compression unit 3 is connected to a high-stage side compression unit 70 a that is driven by an electric motor 70 b of a high-stage side compressor 70 that is located downstream of the compression unit 3.

A gas cooler 71 for cooling the refrigerant is connected to the subsequent stage of the compression unit 70a, and the expansion unit 2 of the scroll type fluid machine 1 is connected between the outlet of the gas cooler 71 and the inlet of the evaporator (heat absorber) 73. ing. The refrigerant from the gas cooler 71 is sucked into the expansion side suction chamber 19 of the expansion unit 2 from the expansion side suction pipe 16 described above. Further, the refrigerant is sent from the expansion section 2 of the scroll type fluid machine 1 to the evaporator 73 via the expansion side discharge pipe 17. The refrigerant discharged from the evaporator 73 is sucked into the compression unit 3 of the scroll type fluid machine 1 from the compression side suction pipe 23.

(6) Operation of Refrigeration Apparatus RC Next, the operation of the refrigeration apparatus RC including the scroll fluid machine 1 will be described. In addition, operation | movement at the time of starting of freezing apparatus RC is mentioned later. The intermediate pressure refrigerant (carbon dioxide refrigerant) boosted by the low-stage compression section 3 driven by the expansion section 2 of the scroll type fluid machine 1 is sent from the compression-side discharge pipe 18 to the high-stage compressor 70. Further, the pressure is further increased by the compression unit 70a driven by the electric motor 70b, and becomes high pressure (supercritical). This high-pressure refrigerant is cooled by the gas cooler 71 in the supercritical state, and then taken into the expansion section 2 of the scroll type fluid machine 1 from the expansion side suction pipe 16 and expanded and depressurized.

When the refrigerant expands isentropically in the expansion section 2, the movable scroll 7 revolves and the power is recovered. The revolving orbiting motion of the movable scroll 7 causes the compressor 3 to operate as a low-stage compressor. The refrigerant expanded in the expansion section 2 is heated by the evaporator 73 (or the object is thereby cooled), and is again sucked into the compression section 3 of the scroll type fluid machine 1 through the compression side suction pipe 23.

In this way, the compression unit 3 of the scroll fluid machine 1 takes part of the compression process of the refrigeration cycle of the refrigeration apparatus RC (low stage side), and the compression part 70a of the compressor 70 on the high stage side remains the compression process ( Take the higher stage). The compression power in the compression unit 3 is covered by the recovery power in the expansion unit 2.

(6-1) State of the check valve device 66 during operation of the refrigeration apparatus RC As described above, the interior of the housing 4 including the back pressure chamber 52 is compressed from the compression side discharge hole 32 during operation of the scroll type fluid machine 1. The discharge pressure of the compression unit 3 discharged into the side discharge chamber 22 is maintained. Therefore, the pressure of the compression side discharge chamber 22 (pressure on the discharge side of the compression unit 3) is the same as the pressure (back pressure) of the back pressure chamber 52 communicating with the lubricating oil chamber 26 via the oil supply passage 28. The reed valve 67 of the check valve device 66 is spaced from the valve seat 47a to open the outlet of the oil return passage 47, and allows the lubricating oil from the compression side discharge chamber 22 to the lubricating oil chamber 26 on the back pressure chamber 52 side to pass therethrough.

Accordingly, the lubricating oil maintained at the discharge pressure of the compression unit 3 is supplied to the back pressure chamber 52 through the oil return passage 47, the lubricating oil chamber 26, and the oil supply passage 28. 7 is urged against the fixed scroll 6 by the discharge pressure of the compression unit 3, and the expansion and compression (low stage) of the refrigerant is stably performed in the expansion unit 2 and the compression unit 3 of the scroll type fluid machine 1. .

(6-2) Operation at the time of starting the refrigeration apparatus RC (action of the check valve device 66)
Next, the operation at the time of starting the refrigeration apparatus RC will be described with reference to FIG. Assuming that the high-stage compressor 70 and the scroll type fluid machine 1 are stopped before t1 in FIG. 6, the freezing of the refrigeration apparatus RC including the housing 4 and the scroll unit 8 of the scroll type fluid machine 1 is performed. The entire cycle has an equilibrium pressure of about 6 MPa.

When the high-stage compressor 70 is started at time t1 in FIG. 6 from this equilibrium pressure state, the discharge pressure P1 of the compressor 70 (pressure at the inlet sucked into the expansion section 2 from the expansion-side suction pipe 16) is It rises from the equilibrium pressure and reaches about 10 MPa during operation. Further, the pressure P2 of the refrigerant that expands in the expansion section 2 and exits from the expansion side outlet pipe 17 (pressure at the outlet of the expansion section 2 = pressure on the suction side of the compression section 3) decreases from the equilibrium pressure.

On the other hand, since the refrigerant is sucked into the compressor 70 from the compression side discharge chamber 22 through the compression side discharge pipe 18 from the time when the high stage side compressor 70 is started up, the pressure P3 ( The pressure in the compression side discharge chamber 22) decreases rapidly and becomes lower than the pressure P2 on the suction side of the compression unit 3. Due to the rapid pressure drop in the compression side discharge chamber 22, the pressure in the compression side discharge chamber 22 (compression unit 3) is higher than the pressure P 4 in the back pressure chamber 52 (pressure in the lubricating oil chamber 26 communicating with the back pressure chamber 52). Therefore, the reed valve 67 of the check valve device 66 contacts and closes the valve seat 47a at the outlet of the oil return passage 47.

As a result, the pressure P4 in the back pressure chamber 52 does not drop abruptly like the pressure P3 on the discharge side of the compression section 3, and the back pressure of the movable scroll 7 is secured, so that the scroll fluid machine 1 can be started. Become. However, due to the small hole 67a, the pressure P4 in the back pressure chamber 52 gradually decreases.

Further, as described above, the pressure P3 on the discharge side of the compression unit 3 (pressure on the compression side discharge chamber 22) is lower than the pressure on the suction side of the compression unit 3, so that the scroll unit 8 of the scroll type fluid machine 1 has Generates a starting torque. Thereby, the scroll type fluid machine 1 becomes easy to start and starts at time t2.

When the scroll fluid machine 1 is activated, the refrigerant starts to be compressed in the compression chamber of the compression unit 3, so that the pressure in the compression side discharge chamber 22 which is the pressure P3 on the discharge side of the compression unit 3 also rises, and eventually the compression unit 3 and the pressure P2 in the back pressure chamber 52 becomes the same as about 5 MPa. As a result, the reed valve 67 of the check valve device 66 opens the outlet of the oil return passage 47, and thereafter, the pressure P3 on the discharge side of the compression unit 3 is supplied as the back pressure P4.

As described above, the back pressure chamber 52 formed on the back surface 7c side opposite to the base surface 7b of the movable scroll 7 of the scroll type fluid machine 1, and the discharge side (compression side discharge chamber 22) of the compression unit 3 And an oil return path 47 as a communication path for communicating with the back pressure chamber 52, and a direction from the discharge side of the compression unit 3 to the lubricating oil chamber 26 on the back pressure chamber 52 side provided in the oil return path 47. Is provided with the check valve device 66 in the forward direction, so that the refrigerant is sucked into the compressor 70 on the higher stage side than the discharge side of the compression unit 3 of the scroll type fluid machine 1, and the compressor on the higher stage side. The scroll type fluid machine 1 of the present invention is used in the refrigeration apparatus RC that sucks the high-pressure refrigerant compressed in 70 into the expansion part 2 of the scroll type fluid machine 1 and the compressor 70 on the high stage side is started up. The refrigerant is sucked from the compression unit 3 of the scroll type fluid machine 1. Even if, disadvantage that the pressure (back pressure) is rapidly reduced in the back pressure chamber 52 of the scroll type fluid machine 1 at the start of the compressor 70 of the high-stage side is prevented by the check valve device 66.

As a result, the refrigerant is sucked from the compressor 3 of the scroll type fluid machine 1 from the start of the high-stage compressor 70 without bypassing the compressor 3 of the scroll type fluid machine 1 as in the prior art. The movable scroll 7 is pressed against the fixed scroll 6 without being peeled off from the fixed scroll 6, and the scroll fluid machine 1 can be activated. Then, by sucking the refrigerant from the discharge side of the compression unit 3 with the high-stage compressor 70, the pressure on the discharge side of the compression unit 3 becomes lower than the pressure on the suction side of the compression unit 3. Thereby, since the starting torque is generated in the scroll type fluid machine 1, it is possible to start up more easily than in the prior art.

In this case, since the check valve device 66 is provided with a small hole 67a that communicates the lubricating oil chamber 26 on the back pressure chamber 52 side with the discharge side (compression side discharge chamber 22) of the compression section 3, After starting up the compressor 70, the pressure gradually passes through the small hole 67 a of the check valve device 66 into the compression side discharge chamber 22 that is the discharge side of the compression unit 3. That is, the pressure in the back pressure chamber 52 that has risen to an equilibrium pressure higher than the pressure on the discharge side of the compression unit 3 during the stop is gradually reduced after the high-stage compressor 70 is started. Become. As a result, the pressure P4 in the back pressure chamber 52 can be lowered to the pressure P3 on the discharge side of the compression unit 3 at an early stage after the scroll type fluid machine 1 is started, and the back pressure applied to the movable scroll 7 is quickly and appropriately set. Value.

Further, in the embodiment, the main frame 9 is provided with a pedestal portion 9 b that supports the movable scroll 7 so as to be capable of revolving and turning at the outer peripheral portion of the back surface 7 c of the movable scroll 7, and an oil return path 47 is formed in the main frame 9. Since the check valve device 66 is composed of the reed valve 67 attached to the main frame 9 so as to close the outlet of the oil return channel 47 on the back pressure chamber 52 side, the oil return channel 47 and the check valve device are configured. 66 can be realized with a simple configuration, and the structure can be simplified. In the embodiment, since the small hole 67a is formed in the reed valve 67, the narrow passage of the check valve device 66 can be realized with a simple configuration. The scroll fluid machine 1 of the present invention is particularly effective for the refrigeration apparatus RC that uses carbon dioxide as a working fluid.

(7) Other Examples of Check Valve Device 66 In the above embodiment, a small hole 67a is formed in the reed valve 67 of the check valve device 66 to form a narrow passage. However, the present invention is not limited thereto, and a small groove is provided in the valve seat 47a. Even when the reed valve 67 is in contact with the valve seat 47a, a narrow passage communicating the oil return passage 47 and the lubricating oil chamber 26 may be formed.

DESCRIPTION OF SYMBOLS 1 Scroll type fluid machine 2 Expansion part 3 Compression part (low stage side)
6

Fixed scroll

6a,

7a Substrate

6b, 7b Base surface 7 Movable scroll 8 Scroll unit 9 Main frame 22 Compression side discharge chamber 26 Lubricating oil chamber 47 Oil return path (communication path)
47a Valve seat 52 Back pressure chamber 66 Check valve device 67 Reed valve 67a Small hole (narrow passage)
RC refrigeration cycle

Claims

It is composed of a fixed scroll and a movable scroll each formed with a spiral wrap facing each base surface of each substrate, and by expanding the working fluid in an expansion chamber formed between the wraps of both scrolls, An expansion part that collects power by revolving orbiting the movable scroll, and a low stage that compresses the working fluid in a compression chamber formed between the laps of the scrolls by the power recovered by the expansion part. The working fluid compressed by the compression portion is sucked into a high-stage compressor, and the high-pressure working fluid compressed by the high-stage compressor is supplied to the expansion portion. In the scroll type fluid machine
A back pressure chamber formed on the back side opposite to the base surface of the movable scroll;
A communication path for communicating the discharge side of the compression section and the back pressure chamber;
A scroll type fluid machine, comprising: a check valve device provided in the communication path and having a forward direction from the discharge side of the compression unit toward the back pressure chamber side.
The scroll type fluid machine according to claim 1, wherein the check valve device includes a narrow passage communicating the back pressure chamber side and the discharge side of the compression unit.
A frame having a pedestal for supporting the movable scroll so as to be capable of revolving orbiting at the outer peripheral portion of the back surface of the movable scroll;
The communication path is formed in the frame,
The said check valve apparatus is comprised from the reed valve attached to the said flame | frame so that the exit by the side of the said back pressure chamber of the said communicating path may be plugged up. Scroll type fluid machine.
The scroll fluid machine according to claim 3, wherein a small hole is formed in the reed valve.
4. The scroll type fluid machine according to claim 3, wherein a small groove is formed in a valve seat of the reed valve.
A scroll type fluid machine according to any one of claims 1 to 5 and a high stage side compressor, wherein the high stage is configured to be higher than a discharge side of a compression unit of the scroll type fluid machine. The working fluid is sucked into the compressor on the side, the high-pressure working fluid compressed by the high-stage compressor is sucked into the expansion portion of the scroll type fluid machine, and
A refrigerating apparatus, wherein the working fluid is sucked from a compression section of the scroll type fluid machine from the time of starting the high stage compressor.
The refrigeration apparatus according to claim 6, wherein carbon dioxide is used as the working fluid.