JP2008297978A - Scroll type fluid machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a scroll-type fluid machine capable of stabilize the amount of lubrication oil supplied to an intake chamber and improving volume efficiency of the fluid machine through simplification. <P>SOLUTION: The fluid machine comprises an opening part 74 formed at circumferential end faces 64c, 64d of a seal ring 64 with stepped parts 72, 72 confronting to each other to have clearance parts 76, 76, a communication groove 68 formed on a rear face 44 of a movable scroll 34, communicating a high-pressure chamber 62 with the intake chamber side by intermittently striding over a slidable contact surface 64a except the opening part along with turning movements of the movable scroll, and forming a back pressure chamber 70 with intermediate pressure lower than that of the high-pressure chamber and higher than that of the intake chamber in a space between a rear face and a seating face 50, and a rotation preventing mechanism 84 for preventing rotation of the seal ring in an annular groove 66. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a scroll type fluid machine, and more particularly to a scroll type fluid machine suitable for use in a refrigeration air conditioner or a heat pump type hot water heater.

This type of scroll-type fluid machine, for example, a hermetic scroll compressor, sucks, compresses and discharges a working fluid (hereinafter referred to as a refrigerant) containing lubricating oil by rotating the movable scroll with respect to the fixed scroll in the housing. A high-pressure chamber in which the refrigerant discharge pressure acts and a suction chamber in which the refrigerant suction pressure acts are formed in the housing.
Here, a frame that supports the movable scroll so as to be capable of turning motion on the pedestal surface is fixed to the housing, and a seal ring that is in sliding contact with the back surface of the movable scroll is supported on the pedestal surface. A communication groove that connects the high-pressure chamber and the low-pressure chamber is formed on the back surface of the movable scroll, and the communication groove is intermittently positioned on the seal ring with the orbiting motion of the movable scroll. There is known a back pressure mechanism that forms a back pressure chamber having an intermediate pressure lower than that of the high pressure chamber and higher than that of the suction chamber between the pedestal surface of the frame and the pedestal surface (see, for example, Patent Document 1).
Japanese Patent No. 3696683

By the way, as disclosed in the above prior art, an abutment portion is formed in the seal ring, and the abutment portion allows thermal expansion of the seal ring.
However, in the above prior art, no special consideration is given to the positional relationship between the abutment portion and the communication groove and the point that the seal ring rotates in the circumferential direction in accordance with the revolving turning motion of the movable scroll. There is a concern that the volume efficiency of the compressor may be reduced due to an increase in the amount of lubricating oil supplied.

  The present invention has been made in view of such problems, and the object of the present invention is to stabilize the amount of lubricating oil supplied to the suction chamber and to simplify the volume efficiency of the fluid machine. It is to provide a scroll type fluid machine.

  In order to achieve the above object, a scroll type fluid machine according to claim 1 is configured to perform a series of processes from suction to discharge of a working fluid including lubricating oil by rotating the movable scroll with respect to the fixed scroll in the housing. A scroll type fluid machine configured to form a high-pressure chamber in which a discharge pressure of a working fluid acts in a housing and a suction chamber in which a suction pressure of the working fluid acts, and is fixed to the housing and swivels the movable scroll on a pedestal surface A frame that is movably supported, an annular groove formed on the pedestal surface, a seal ring that is fitted in the annular groove and has a slidable contact surface that slidably contacts the back surface of the movable scroll, and a circumferential end surface of the seal ring. A stepped portion having a complementary shape is formed on the back surface with a gap portion in the circumferential direction, and a sliding contact other than the joint portion is formed on the back surface along with the turning movement of the movable scroll. A communication groove that intermittently straddles the top and communicates the high-pressure chamber and the suction chamber side, and forms a back pressure chamber in the space between the back surface and the pedestal surface that has a lower pressure than the high-pressure chamber and a higher intermediate pressure than the suction chamber. And a rotation blocking mechanism for blocking the rotation of the seal ring in the annular groove.

According to a second aspect of the present invention, in the first aspect of the present invention, the rotation preventing mechanism is formed with a convex portion formed on the inner peripheral surface of the seal ring, and a convex portion formed by cutting out the inner peripheral wall of the annular groove. It is characterized by comprising a cutout portion to be engaged.
Further, the invention described in claim 3 is characterized in that, in claim 2, the convex portion has a height substantially equal to the groove depth of the annular groove.

Furthermore, the invention described in claim 4 is characterized in that, in claim 2 or 3, the notch portion is formed to have a notch width having a gap of substantially the same size as the gap portion with respect to the convex portion.
The invention according to claim 5 is characterized in that in any one of claims 1 to 4, the working fluid is a refrigerant made of carbon dioxide.

  According to the scroll type fluid machine of the first aspect of the present invention, since the rotation preventing mechanism is provided, the seal ring is rotated in the annular groove in accordance with the turning motion of the movable scroll, and the communication groove is slidably contacted at the joint portion. It can avoid being positioned on the surface. Here, since the step portion having a complementary shape on the peripheral end surface of the seal ring has a gap portion in the circumferential direction and is opposed to the gap portion, the communication groove is positioned on the step portion so that the gap portion is formed. It is possible to prevent the amount of the lubricating oil contained in the working fluid from increasing from the high-pressure chamber to the back-pressure chamber from increasing due to the presence of the portion. This can prevent an increase in the amount of lubricating oil flowing from the high pressure chamber to the back pressure chamber and hence from the back pressure chamber to the suction chamber, and the amount of lubricating oil supplied to the suction chamber can be stabilized to increase the volume efficiency of the scroll type fluid machine. Can improve.

  According to the second aspect of the present invention, the rotation preventing mechanism includes a convex portion formed on the inner peripheral wall of the seal ring and a cutout portion formed by cutting out the inner peripheral wall of the annular groove. Is engaged with the convex portion. Accordingly, it is possible to prevent the rotation of the seal ring with a simple configuration and to prevent the communication groove from being positioned on the sliding contact surface in the joint portion, and thus it is possible to simplify and improve the volume efficiency of the scroll type fluid machine.

  Furthermore, according to the invention described in claim 3, when the convex portion has a height substantially the same as the groove depth of the annular groove, the sliding contact surface between the seal ring and the back surface is formed on the convex portion. Absent. As a result, the communication groove is positioned on the sliding contact surface of the convex portion, so that the area of the sliding contact surface is substantially increased and the straddling amount of the lubricating oil contained in the working fluid from the high pressure chamber to the back pressure chamber is increased. It can be prevented from decreasing. As a result, it is possible to prevent a decrease in the amount of lubricating oil flowing from the high pressure chamber to the back pressure chamber, and hence from the back pressure chamber to the suction chamber, and the amount of lubricating oil supplied to the suction chamber is stabilized, thereby improving the volume efficiency of the scroll type fluid machine. Can improve.

Furthermore, according to the invention described in claim 4, the notch is formed with a notch width having a gap of substantially the same size as the gap formed at the abutment with respect to the convex part, so that the seal due to thermal expansion is formed. The stable supply of lubricating oil to the suction chamber can be more reliably performed without hindering the circumferential extension of the ring.
According to the fifth aspect of the invention, since the movable scroll turns in the high rotation range because the working fluid is a refrigerant made of carbon dioxide, the rotation of the seal ring becomes more remarkable. Thus, it is possible to reliably prevent the rotation of the seal ring and improve the volumetric efficiency of the scroll type fluid machine.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a hermetic scroll compressor as an example of a fluid machine according to an embodiment of the present invention. The compressor 1 is incorporated in a refrigeration circuit such as a refrigeration air conditioner or a heat pump type hot water heater. The circuit includes a path through which carbon dioxide refrigerant (hereinafter referred to as refrigerant), which is an example of a working fluid, circulates, and the compressor 1 sucks the refrigerant from the path, compresses the refrigerant, and discharges the refrigerant toward the path.

  The compressor 1 includes a housing 2, and an upper lid 6 and a lower lid 8 are fitted in an airtight manner on the upper side and the lower side of the body portion 4 of the housing 2, respectively. The discharge pressure is acting. A suction pipe 10 for sucking the refrigerant taken in from the circuit is connected to an appropriate position of the body 4, and a discharge pipe 12 for sending the compressed refrigerant in the housing 2 to the circuit is connected to an appropriate position of the upper lid 6. Has been.

An electric motor 14 is accommodated in the body 4, and a rotating shaft 16 is disposed in the motor 14. The rotating shaft 16 is driven by energization of the motor 14. Further, the upper end side of the rotating shaft 16 is rotatably supported by a main shaft frame (frame) 18 via a bearing, and the main shaft frame 18 is fixed integrally to the housing 2.
On the other hand, the lower end side of the rotating shaft 16 is rotatably supported by the countershaft frame 20 via a bearing. An oil pump 22 is attached to the lower end side of the rotary shaft 16, and the pump 22 sucks lubricating oil in an oil storage chamber 24 formed inside the lower lid 8. This lubricating oil ascends in the oil supply passage 26 drilled in the axial direction in the rotary shaft 16 and is supplied from the upper end of the rotary shaft 16 to the motor 14, scroll unit 28, etc. Functions as a sliding surface seal. At this time, the fact that the discharge pressure of the refrigerant acts on the surface of the lubricating oil in the oil storage chamber 26 also contributes to the increase of the lubricating oil in the oil supply passage 26. Further, a lubricating oil inlet 30 is formed at an appropriate position of the countershaft frame 20, and the lubricating oil supplied to each sliding portion in the compressor 1 is stored in the oil storage chamber 24 via the inlet 30. Is done.

The unit 28 is disposed above the motor 14 in the body 4 and performs a series of processes of refrigerant suction, compression and discharge.
Specifically, the unit 28 includes a movable scroll 34 and a fixed scroll 36, and the movable scroll 34 includes an end plate 38, and a spiral wrap extending toward the end plate 40 of the fixed scroll 36 is integrated with the end plate 38. A spiral wrap that is formed and extends toward the end plate 38 is also formed integrally with the end plate 40 of the fixed scroll 36.

  These spiral wraps cooperate with each other, and form a compression chamber by sucking refrigerant from the outer peripheral side of the end plate 38 and the suction chamber communicating with the suction pipe 10. The compression chamber is moved toward the center of the spiral wrap by the revolving motion of the movable scroll 34 with respect to the fixed scroll 36, and the volume of the compression chamber is reduced, and the above-described series of processes is performed. The rotation of the movable scroll 34 is blocked by a rotation blocking pin (not shown).

  In order to impart a turning motion to the movable scroll 34 described above, a boss 46 is formed on the lower surface side of the end plate 38, that is, on the rear surface 44 side of the movable scroll 34, and this boss 46 is rotatable about an eccentric shaft 48 via a bearing. Supported. The eccentric shaft 48 is integrally formed on the upper end side of the rotary shaft 16, and a predetermined space 52 that allows the movable scroll 34 to turn is formed between the back surface 44 and the pedestal surface 50 of the spindle frame 18. The movable scroll 34 orbits on the pedestal surface 50 by the rotation of the rotating shaft 16.

On the other hand, the fixed scroll 36 is fixed to the spindle frame 18 and the end plate 40 partitions the compression chamber side and the discharge chamber 54 side. The end plate 40 incorporates a back pressure adjusting valve (not shown) that can adjust the pressure in the space 52.
Further, a discharge hole 56 communicating with the compression chamber side is formed at an appropriate position in the center portion of the fixed scroll 36 through the end plate 40, and this discharge hole 56 is disposed on the back side of the fixed scroll 36. The discharge valve 58 is opened and closed. Further, the discharge valve 58 is covered with a discharge head 60, and the sound when the discharge valve 58 is opened is suppressed by the discharge head 60.

  According to the compressor 1 described above, the movable scroll 34 orbits as the rotary shaft 16 rotates. This orbiting movement of the movable scroll 34 sucks the refrigerant in the suction chamber toward the inside of the unit 28, compresses the refrigerant by reducing the volume of the compression chamber, and discharges the compressed high-pressure refrigerant to the discharge hole 56. Then, after circulating in the housing 2, the air is sent out of the compressor 1 through the discharge pipe 12 from the discharge chamber 54.

  On the other hand, the high-pressure lubricating oil pumped up by the pump 22 in combination with the action of the refrigerant discharge pressure is discharged from the oil supply passage 26 at the upper end of the rotary shaft 16, and the spindle frame 18 in which the boss 46 is accommodated. A high pressure chamber 62 for lubricating oil is formed in the boss accommodating portion 18a. The lubricating oil in the high pressure chamber 62 flows down in the housing 2 along the rotary shaft 16 while lubricating the bearings and the like, while forming in the unit 28 through the space 52 and the space 42 formed on the outer peripheral side of the end plate 38 in order. Supplied toward the compression chamber. That is, the spaces 52 and 42 function as an oil guide passage that guides the lubricating oil from the high pressure chamber 62 to the inside of the unit 28.

  Here, the high pressure chamber 62 and the space 52 are partitioned by an annular seal ring 64. The ring 64 is injection-molded from a plastic material, an engineering plastic material, or the like, and is fitted into an annular groove 66 formed on the base surface 50 concentrically with the axis of the rotary shaft 16. An upper surface (sliding contact surface) 64 a of the ring 64 is formed so as to be slidable over the entire periphery of the rear surface 44. Preferably, the ring 64 is pressed and urged against the rear surface 44, so that the upper surface 62 a is surely attached to the rear surface 44. Further, an elastic body such as a leaf spring (not shown) is disposed between the annular groove 66 and the lower surface 64b of the ring 64 so as to be continuously slidably contacted.

  On the other hand, as shown in FIG. 2, referring to a plan view of the movable scroll 34 viewed from the AA direction in FIG. 1, a long groove 68 extending in the radial direction of the movable scroll 34 is formed in the back surface 44. The long groove 68 is positioned so that the high-pressure lubricating oil in the high-pressure chamber 62 can intermittently straddle the ring 64 and flow into the space 52 by moving relative to the ring 64 in accordance with the revolving turning motion of the movable scroll 34. . At this time, by adjusting the set pressure of a back pressure adjusting valve (not shown), a back pressure chamber 70 is formed in the space 52. The back pressure chamber 70 has an intermediate pressure lower than that of the high pressure chamber 62 and higher than that of the suction chamber. A plurality of long grooves 68 may be provided.

  Specifically, as shown in FIG. 3, referring to the enlarged view of the ring 64 seen from the BB direction in FIG. 1, the ring 64 is formed with a predetermined ring width W, and in the circumferential direction of the ring 64. Opposing peripheral end faces 64c and 64d are provided. Step portions 72 having complementary shapes are formed on the peripheral end surfaces 64c and 64d, and the step width W1 of each step portion 72 in the radial direction of the ring 64 is about half of the ring width W. Thus, the stepped portion 72 formed on the peripheral end surfaces 64 c and 64 d constitutes the joint portion 74 of the ring 64.

  The abutment portion 74 has an abutment gap portion (gap portion) 76 on the side of the peripheral end faces 64 c and 64 d in a state where the ring 64 is accommodated in the annular groove 66. The abutment gap 76 has a predetermined gap length so as to allow the circumferential extension caused by the thermal expansion of the ring 64 when the ring 64 is exposed to a high temperature atmosphere during the operation of the compressor 1. Accordingly, the diameter expansion due to the thermal expansion of the ring 64 is allowed.

On the other hand, when the compressor 1 is operated, the inner peripheral surface 64e of the ring 64 is pressed and urged against the outer peripheral wall of the annular groove 66 by the pressure of the high pressure chamber 62, thereby forming the radial seal portion 78 at the joint portion 74. The sealing property of the back pressure chamber 70 is ensured.
Incidentally, four convex portions 80 are formed on the inner peripheral surface 64e of the ring 64 inward. The convex portion 80 has a height that is substantially the same as the groove depth of the annular groove 66, and is disposed at a position different from the abutment portion 74 at an interval of about 90 ° from the center of the ring 64.

On the other hand, as shown in FIG. 4, referring to the plan view of the spindle frame 18 as viewed from the BB direction in FIG. 1, the annular groove 66 in which the ring 64 is accommodated has its inner peripheral wall 66 a and the boss accommodating portion 18 a. The four notches 82 are formed so as to face each other, and each convex portion 80 is engaged with each notch 82 to constitute four engaging portions (rotation prevention mechanisms) 84.
Further, referring to the enlarged view of the engaging portion 84 shown in FIG. 5, the notch portion 82 has a predetermined notch width W <b> 2, and this notch width W <b> 2 is caused by thermal expansion, similarly to the joint gap portion 76. The ring 64 is set in advance so as to allow the circumferential extension of the ring 64.

Hereinafter, the amount of lubricating oil flowing from the high pressure chamber 62 into the back pressure chamber 70 will be described with reference to FIGS.
As shown in FIG. 6, when the long groove 68 is positioned on the ring 64 with the CC direction of FIG. 4 as the longitudinal direction in the process of turning the movable scroll 34, as shown by the dotted arrow in the figure, The high pressure lubricating oil in the high pressure chamber 62 passes through the long groove 68 across the ring 64 and flows into the back pressure chamber 70. The amount of lubricating oil Q flowing in at this time is substantially determined by the ring width W of the ring 64, the time H during which the long groove 68 is positioned on the ring 64, and the pressure P of the high-pressure oil chamber 62.

  On the other hand, as shown in FIG. 7, in the process in which the movable scroll 34 turns with the time H and the pressure P set to the same conditions as in FIG. 6, the turning movement of the movable scroll 34 proceeds from the position CC. It is assumed that the long groove 68 is positioned on the ring 64 with the DD direction of FIG. At this time, since the ring width W is not different from the case of FIG. 6, the lubricating oil having the same lubricating oil amount Q as in the case of FIG. 6 flows into the back pressure chamber 70.

Thus, according to the compressor 1 according to the present embodiment, the ring 64 rotates in the annular groove 66 as the movable scroll 34 pivots by having the engaging portion 84 between the ring 64 and the annular groove 66. In addition, it is possible to avoid the long groove 68 being positioned on the joint portion 74.
Here, as shown in FIG. 8, the ring 64 rotates in the annular groove 66 in accordance with the turning motion of the movable scroll 34, and the long groove 68 is formed on the joint portion 76 with the EE direction of FIG. 4 as the longitudinal direction. Suppose it is positioned. In this case, the lubricating oil flowing into the back pressure chamber 70 from the high pressure chamber 62 flows over the stepped portion 72, and the straddling width is a step width W1 that is substantially half of the ring width W. That is, if the time H and the pressure P are the same as in the case of FIGS. 6 and 7, the ring width W is substantially reduced and the lubricating oil amount Q is increased by, for example, about twice, and the volume efficiency of the compressor 1 is increased. Will drop significantly.

  On the other hand, in the present embodiment, the high-pressure lubricating oil in the high-pressure chamber 62 straddles the ring 64 at the joint portion 74 by simple and inexpensive processing that only forms the engaging portion 84 including the convex portion 80 and the notch portion 82. Can be prevented. Therefore, it is possible to prevent an increase in the amount of lubricating oil Q flowing from the high-pressure chamber 62 into the back pressure chamber 70 and hence from the back pressure chamber 70 into the suction chamber, and the amount of lubricating oil Q supplied to the suction chamber can be stabilized. Volume efficiency can be simplified and improved.

Moreover, by forming the convex portion 80 at substantially the same height as the groove depth of the annular groove 66, the ring width W is substantially increased by the convex portion 80 even if the long groove 68 is positioned on the engaging portion 84. Thus, it is possible to prevent the amount Q of the lubricating oil from decreasing, and it is possible to reliably realize the stable supply of the lubricating oil from the high pressure chamber 62 to the suction chamber.
Furthermore, since the notch width W2 of the notch 82 is set in advance so as to allow the circumferential extension of the ring 64 due to thermal expansion, the suction chamber can be moved from the high pressure chamber 62 without hindering the thermal expansion of the ring 64. A stable supply of lubricating oil to the can be further reliably performed.

The description of one embodiment of the present invention is finished above, but the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above-described embodiment, the engaging portion 84 is disposed at a position different from the abutment portion 74 at an interval of approximately 90 ° from the center of the ring 64, but is not limited to this arrangement.
Further, in the above embodiment, the convex portion 80 is formed at substantially the same height as the groove depth of the annular groove 66, but the long groove 68 is not positioned not only on the joint portion 74 but also on the engaging portion 84. If it is reliably formed, the height of the convex portion 80 may be the same as the height of the ring 64.

Further, in the above embodiment, the long groove 68 is formed as a communication groove between the high pressure chamber 62 and the back pressure chamber 70, but the high pressure chamber 62 and the back pressure chamber 70 are intermittently communicated with the turning motion of the movable scroll 34. The shape of the communication groove is not limited to the long groove shape.
Furthermore, in the above-described embodiment, the four engaging portions 84 are formed, but the number is not limited to four, and at least one or more may be formed, and the shape of the ring 64 is not limited to the shape of the engaging portion 84. Other rotation blocking mechanisms may be used as long as the rotation can be blocked.

Moreover, in the said embodiment, although carbon dioxide is used as a refrigerant | coolant, it is not limited to this. However, by using carbon dioxide as a refrigerant, the movable scroll 34 turns in a high rotation range, so that the rotation of the ring 64 becomes more remarkable. However, the above configuration reliably prevents the rotation of the ring 64 and compresses it. The volumetric efficiency of the machine 1 can be improved reliably.
Furthermore, although the said embodiment demonstrated the sealed scroll compressor integrated in refrigeration circuits, such as a refrigeration air conditioner and a heat pump type hot water heater, it is not restricted to this and compressors or expansion other than a sealed type in various fields | areas It is applicable to a scroll type fluid machine such as a machine.

  Finally, it goes without saying that the above-described various modifications also have the effect that the volume efficiency of the fluid machine can be simplified and improved.

1 is a longitudinal sectional view showing a hermetic compressor according to an embodiment of the present invention. It is a top view of the movable scroll seen from the AA direction of FIG. It is a top view of the seal ring seen from the AA direction of FIG. FIG. 2 is a plan view of a spindle frame as seen from the BB direction in FIG. 1. It is a principal part enlarged view of FIG. It is a figure which shows the flow of the lubricating oil from a high pressure chamber to a back pressure chamber when a long groove is located on a seal ring by making CC direction of FIG. 4 into a longitudinal direction. It is a figure which shows the flow of the lubricating oil from a high pressure chamber to a back pressure chamber when a long groove is positioned on a seal ring by making DD direction of FIG. 4 into a longitudinal direction. It is a figure which shows the flow of the lubricating oil from a high pressure chamber to a back pressure chamber when a long groove is located on a seal ring by making EE direction of FIG. 4 into a longitudinal direction.

Explanation of symbols

1 Compressor (scroll type fluid machine)
2 Housing 18 Spindle frame (frame)
34 Movable scroll 36 Fixed scroll 42 Space 44 Back surface 50 Base surface 52 Space 62 High pressure chamber 64 Seal ring 64a Upper surface (sliding contact surface)
64c peripheral end surface 64d peripheral end surface 64e inner peripheral surface 66 annular groove 66a inner peripheral wall 68 long groove (communication groove)
70 Back pressure chamber 72 Stepped portion 74 Abutting portion 76 Abutting gap portion (gap portion)
80 Convex part 82 Notch part 84 Engagement part (rotation prevention mechanism)

Claims (5)

A high-pressure chamber in which a series of processes from suction to discharge of a working fluid including lubricating oil is performed by rotating the movable scroll with respect to the fixed scroll in the housing, and the discharge pressure of the working fluid acts in the housing; A scroll type fluid machine that forms a suction chamber on which a suction pressure of the working fluid acts,
A frame that is fixed to the housing and supports the movable scroll so as to be capable of rotating on the pedestal surface;
An annular groove formed in the pedestal surface;
A seal ring that is fitted in the annular groove and has a sliding contact surface that is in sliding contact with the back surface of the movable scroll;
A stepped portion formed on the peripheral end surface of the seal ring and having a complementary shape has a gap in the circumferential direction, and an abutting portion facing each other,
The high pressure chamber and the suction chamber side are communicated intermittently across the sliding contact surface other than the abutment portion with the orbiting scroll turning motion, and the back surface and the pedestal surface are connected to each other. A communication groove that forms a back pressure chamber that is an intermediate pressure lower than the high pressure chamber and higher than the suction chamber in a space between
A scroll type fluid machine comprising: a rotation prevention mechanism for preventing rotation of the seal ring in the annular groove.   The rotation prevention mechanism includes a convex portion formed on the inner peripheral surface of the seal ring, and a cutout portion formed by cutting out the inner peripheral wall of the annular groove and engaging the convex portion. The scroll type fluid machine according to claim 1.   The scroll fluid machine according to claim 2, wherein the convex portion has a height substantially the same as the groove depth of the annular groove.   The scroll-type fluid machine according to claim 2 or 3, wherein the notch is formed to have a notch width having a gap of substantially the same size as the gap with respect to the convex part.   The scroll fluid machine according to any one of claims 1 to 4, wherein the working fluid is a refrigerant made of carbon dioxide.

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