JPH1122660A - Scroll compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure sealing property, and improve compression performance and reliability by guiding gas pressure in the synthetic force direction of the shaft direction and the direction orthogonal to the shaft direction to a seal member, and pressing and energizing the seal member. SOLUTION: Notch parts 36 are arranged in plural places by leaving a prescribed interval in the circumferential direction of a hookingly fitting projection part 17, and high pressure gas introduced through a delivery gas guide hole 17a of the hookingly fitting projection part 17 from a high pressure chamber 22, is guided in a recessed groove 35. Gas pressure to a seal ring 16 in the recessed groove 35 becomes the total of gas pressure introduced along a clearance (k) between an upper boss part 12c and the hookingly fitting projection part 17. As a result, it energizes a seal member by becoming the synthetic force direction of force to push up the seal ring 16 in the shaft direction and force which is the direction orthogonal to the shaft direction and expands the seal ring 16 in the radial direction, that is, force to push the seal ring 16 obliquely upward. In this way, even when a compressor is started, the seal ring 16 is quickly moves, and reliably seals the high pressure side and the low pressure side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scroll compressor used as a compressor constituting a refrigeration cycle of an air conditioner, for example.

[0002]

2. Description of the Related Art For example, in a compressor constituting a refrigeration cycle of an air conditioner, the motion noise is extremely low and the number of parts is small because there is no need for a suction valve or a discharge valve as compared with a normal rotary compressor. There is a tendency for scroll type compressors having good compression performance to be used frequently.

[0003] In this type of scroll compressor, a fixed scroll wing and an orbiting scroll wing are engaged with each other.
A compression space is formed by the wings and the end plates of the scrolls, and the orbiting scroll is swirled to suck the gas to be compressed into the compression space, compressed and discharged.

Incidentally, the compression space of this scroll compressor is not always in a normal pressure state. For example, in the case of a liquid back operation in which a liquid refrigerant is sucked and compressed, the compression space falls into an abnormally pressurized state. If this state continues for a long time, a large stress is applied to the wings of each scroll, and there is a possibility that the scroll may eventually break.

Therefore, a so-called compliance means is employed in which the fixed scroll is supported so as to be movable in the axial direction, and when the compression space is in an abnormally pressurized state, the gap with the orbiting scroll is expanded to allow gas to escape. It became so.

[0006]

A scroll compressor provided with such compliance means to improve safety and reliability, but has a problem in the construction of the seal between the fixed scroll and the compliance means. Have left.

For example, as shown in FIG. 6, a compliance means K guides the gas after compression between the back pressure plate a and the fixed scroll b to provide a fixed scroll b.
A high pressure chamber d for applying a high back pressure to the fixed scroll b and an intermediate pressure chamber e for introducing an intermediate back pressure to the fixed scroll b by introducing the gas during compression.

A sealing member s for sealing the high pressure chamber d and the intermediate pressure chamber e is interposed between the back pressure plate a and the fixed scroll b. Here, a piston ring-shaped sealing member s is used. Things are used.

This piston ring-shaped seal member s is characterized by being inexpensive and easy to insert during assembly. However, when the compressor was actually started, there was a concern about the sealing performance, and even when the fixed scroll b was not properly assembled, the sealing performance was adversely affected.

[0010] The sealing property will be described in more detail. As shown in an enlarged view in FIG. 8, a boss f is integrally provided at the center of the end plate portion of the fixed scroll b, and the inside of the boss f is formed in the high pressure chamber d (or the high pressure chamber d). An intermediate pressure chamber e) is formed.

On the other hand, an engaging projection g integrally provided with the back pressure plate a is engaged with a predetermined gap on the outer peripheral surface of the boss f. A concave groove i is provided facing the outer peripheral surface of the boss f with which the engaging projection g engages, and the seal member s is housed therein.

The seal member s has a rectangular cross section, and has a cut in a part so as to be freely expandable in the radial direction. Then, the seal member s is pushed down by the compressed gas filling the high-pressure chamber d, and seals the high-pressure chamber d.

However, the clearance k between the outer peripheral surface of the boss f and the inner peripheral surface of the engaging projection g is small, and the amount of the compressed gas guided there is small. Therefore, in particular, when the gas pressure at the time of starting the compressor is low, the pushing force on the seal member s by the gas guided into the concave groove i via the clearance k is weak.

If the clearance k is made sufficiently wide,
Although the amount of flowing gas becomes large and the sealing member s is pushed down with a strong force, the area for supporting the sealing member s is reduced this time, causing a problem in stability. In addition, there is no force to positively expand the seal member s in the radial direction of the engaging projection g in the inner peripheral surface direction. For this reason, especially, the sealing effect at the time of startup is small, and the startup rise is delayed.

The scroll compressor shown in FIG. Accordingly, although the configuration is basically the same, no particular description is given. However, the seal member s1 here is a backup seal ring having a U-shaped cross section.

The seal ring s1 with a backup having a U-shaped cross section is expensive in itself and has an adverse effect on cost, and requires a large force to insert it into the mounting groove j at the time of assembling. It is bad.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide cost and assembly on the assumption that a so-called compliance means for supporting a fixed scroll movably in an axial direction is provided. An object of the present invention is to provide a scroll compressor in which sealing performance is ensured without being affected by workability and compression performance and reliability are improved.

[0018]

According to a first aspect of the present invention, there is provided a scroll type compressor in which wings of a fixed scroll and wings of an orbiting scroll are engaged with each other. In a scroll compressor in which a compression space is formed by a fixed scroll and an end plate of an orbiting scroll, a mounting member for mounting the fixed scroll movably in the axial direction, and a gas pressure acting on the rear side of the fixed scroll, In the operating state, back pressure is applied to the fixed scroll to restrict axial movement, and in the event of abnormal pressure rise in the compression space, the fixed scroll is allowed to move in the axial direction to increase the clearance between the orbiting scroll and the gas in the compression space. Back pressure applying mechanism for relieving pressure, a seal member for sealing back pressure by the back pressure applying mechanism on the back side of the fixed scroll, and a shaft with respect to the seal member. The direction and the axial direction to guide the gas pressure in the resultant force direction and the direction perpendicular to, is characterized in that the sealing member comprises a gas pressure acting portion which presses and biases.

According to a second aspect of the present invention, in the scroll compressor according to the first aspect, the back pressure applying mechanism includes a back pressure chamber formed by a fixed scroll end plate rear side and a back pressure plate; A discharge pressure guide that guides the compressed high-pressure gas from the compression space to increase the pressure in the back pressure chamber, and the seal member is movably accommodated in a groove provided along the periphery of the back pressure chamber. And a seal ring that can be expanded in the radial direction, and the gas pressure acting portion is a cutout portion that guides the gas pressure so as to press the seal ring in an oblique direction with respect to the peripheral surface of the back pressure chamber. It is characterized by the following.

According to a third aspect, in the scroll compressor according to the first aspect, the back pressure applying means includes a first back pressure chamber and a second back pressure chamber formed on the back side of the fixed scroll head. A discharge pressure guide for guiding the compressed gas to the first back pressure chamber to make it a discharge pressure, and guiding the gas in the middle of compression from the compression space to the second back pressure chamber so that the second back pressure chamber is in the middle. And an intermediate pressure guide portion for increasing the pressure. At least one of the intermediate pressure guide portion and the discharge pressure guide portion is provided with the seal member and the gas pressure acting portion.

According to a fourth aspect of the present invention, in the scroll type compressor according to the second or third aspect, the concave groove is formed on the back side of the fixed scroll head, and the seal ring is pressed against the back pressure plate. It is characterized by close contact.

According to a fifth aspect, in the scroll compressor according to the second or third aspect, the concave groove is formed in the back pressure plate, and the seal ring is pressed against the back side of the fixed scroll end plate. It is characterized by close contact.

According to a sixth aspect of the present invention, in the scroll compressor according to the fourth aspect, the gas pressure acting portion is a drill hole provided in the fixed scroll along the axial direction.

According to a seventh aspect of the present invention, in the scroll compressor according to the second aspect, a gap between the side surface of the seal ring and a surface of the concave groove in a direction perpendicular to the axial direction is c, and the peripheral surface of the back pressure chamber and the peripheral surface of the fixed scroll. When the clearance with the surface is L, the following conditions are set.
c <L By providing a means for solving the above problems,
According to the first to seventh aspects of the present invention, the sealing property of the seal member is ensured not only at the time of startup of the compressor but also during the normal operation, and the operation of the compressor is facilitated.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a scroll compressor used in, for example, a refrigerating apparatus. In the drawing, reference numeral 1 denotes a closed case, and a support frame 2
Are provided to rotatably support the rotating shaft 3.

A compression mechanism 4 to be described later is connected to the upper portion of the support frame 2 of the rotary shaft 3, and an electric motor portion including a stator and a rotor (not shown) is provided below the support frame 2 of the rotary shaft 3.

The compression mechanism 4 is provided with the support frame 2
A orbiting scroll 11 rotatably supported via a thrust receiving plate 10, a fixed scroll 12 meshed with the orbiting scroll 11, an attachment member 13 for supporting the fixed scroll 12 movably in the axial direction, and a fixed And a back pressure applying mechanism 14 for applying a gas pressure to the back side of the scroll 12.

The orbiting scroll 11 includes the rotary shaft 3
A lower boss portion 11c engaging with the upper end eccentric portion 3a is integrally provided with a mirror plate portion 11a and a spiral wing portion 11b integrally formed on the upper surface side of the mirror plate portion 11a.

The fixed scroll 12 has a mirror plate 12a.
And a spiral wing 12 protruding integrally with the lower surface of the end plate 12a and meshing with the wing 11b of the orbiting scroll 11.
b and an upper boss portion 12c, which will be described later, which is integrally provided at the center of the end plate portion 12a.

A compression space S is formed by the end plates 11a and 12a of the orbiting and fixed scrolls 11 and 12 and the wings 11b and 12b. , And at the same time, its volume is reduced so that a compression action can be performed.

Above the fixed scroll 12, the peripheral end is attached and fixed to the sealed case 1, so that the back pressure plate 18 that partitions the inside of the sealed case 1 into the upper end side space T and the entire space M other than the upper end side space T. Is provided.

The back pressure plate 18 has a valve seat 20 provided with a check valve 19 protruding therefrom, and communicates with the discharge port 15.
In other words, the discharge port 15 communicates with the upper end space of the back pressure plate 18 via the valve seat 20 having the check valve 19.

On the lower surface side of the back pressure plate 18, an engaging projection 17 which is inserted into an upper boss portion 12c provided on the fixed scroll end plate portion 12a and is in a sealed state via a sealing member 16 is integrally projected. Is established.

The engaging projection 17 is provided with a discharge gas guide hole 17a along the axis, and communicates the discharge port 15 with the back pressure plate valve seat 20 through the upper boss 12c. I do.

That is, it is surrounded by the upper boss portion 12c protruding around the discharge port 15 of the fixed scroll 12, the back pressure plate engaging projection 17 and the valve seat portion 20, and discharges from the compression space S through the discharge port 15. A high-pressure chamber 22 filled with the high-pressure gas is formed, and the discharge port 15 serves as a discharge pressure guide.

The upper boss 12c, the back pressure plate 18, the high pressure chamber 22, and the discharge port 15 constitute the back pressure applying mechanism 14. Next, the mounting member 13 will be described. The mounting member 13 includes a guide collar 27 and a mounting bolt body 32.

A flange portion 25 is integrally provided on the outer peripheral portion of the fixed scroll end plate portion 12a, and a plurality of pin holes 26 penetrating the upper and lower surfaces are provided. Hole 2 for each pin
6, the upper end of the guide pin 27 is press-fitted and fixed. The lower portion of the guide pin 27 projects downward from the lower surface of the flange portion 25 along the axial direction of the fixed scroll 12.

The support frame 2 is provided with a plurality of hook holes 28 penetrating the upper and lower surfaces. A guide pin 27 protruding from the fixed scroll flange 25 is inserted into the retaining hole 28.

The clearance between the hooking hole 28 and the guide pin 27 is dimensioned so as to be extremely small. Therefore, the guide pin 27 and the fixed scroll 12 integrated therewith are arranged in the axial direction with respect to the hooking hole 28. It can be moved (slided) freely.

On the other hand, a plurality of guide holes 30 are provided through the fixed scroll flange portion 25 between the pin holes 26. A screw hole 31 is provided to penetrate the support frame 2 at a position facing the guide hole 30.

The mounting bolt body 3 is inserted into the guide hole 30.
2 is loosely inserted, and the screw portion is screwed and fixed to the screw hole 31. The head of the mounting bolt body 32 and the washer 33 have a certain distance from the upper surface of the fixed scroll flange 25, and this gap serves as a predetermined clearance for regulating the moving amount of the fixed scroll 12, as described later. Is set.

On the other hand, a discharge pipe 34 is connected to the upper side surface of the closed case 1, and communicates an upper end side space T in the closed case 1 partitioned by the back pressure plate 18 with a condenser (not shown) of the refrigeration cycle. .

A suction pipe (not shown) is connected to a lower side surface of the closed case 1 to communicate a lower space M in the closed case 1 partitioned by the back pressure plate 18 with an evaporator (not shown) of the refrigeration cycle.

In the scroll compressor constructed as described above, when the electric motor section is energized to drive the compression mechanism section 4, low-pressure refrigerant gas is introduced from the suction pipe into the closed case 1, and The lower space M is filled from the pressure plate 18.

The refrigerant gas is taken into the outer peripheral side of the compression space S formed by the orbiting scroll 11 and the fixed scroll 12. Then, as the orbiting scroll 11 orbits, the compressed space S is gradually transferred from the outer peripheral side to the inner peripheral side of the compression space S, and is compressed due to a decrease in space capacity.

When the pressure rises to a predetermined pressure, the upper end side space T of the back pressure plate 18 is discharged from the discharge port 15 through the high pressure chamber 22.
To the outside condenser through the discharge pipe 34.

The high-pressure refrigerant gas discharged from the discharge port 15 with the compression action in the compression space S once fills the high-pressure chamber 22, and applies a high-pressure back pressure to the central portion of the fixed scroll head plate 12a.

The fixed scroll 12 is pressed against the orbiting scroll 11 in the axial direction by the high back pressure in the high pressure chamber 22. Therefore, in the compression space S formed by the fixed scroll 12 and the orbiting scroll 11, an optimal clearance is maintained between the scrolls.

The thrust force generated between the support surface of the support frame 2 for the orbiting scroll 11 and the sliding contact surface of the orbiting scroll head 11a is significantly reduced as compared with the conventional one, and the compression performance is improved. Leads to.

Depending on operating conditions, liquid refrigerant may be sucked into the compression space S, and at this time, the pressure is increased to an abnormally high pressure.
The pressure in the compression space S exceeds the back pressure of the back pressure applying mechanism 14, and as a result, the fixed scroll 12 moves in the axial direction.

Guide pin 2 integral with fixed scroll 12
Numeral 7 is guided by a hook hole 28 provided in the support frame 2 and floats. The clearance of the compression space S expands at once, and the abnormally high pressure gas in the compression space S instantaneously escapes into the closed case 1.

The so-called compliance function is exerted, and the stress applied to the orbiting and fixed scrolls 11, 12 and particularly to the wing portions 11b, 12b is instantaneously eliminated.

When the fixed scroll 12 rises, the upper surface of the flange portion 25 comes into contact with the head of the mounting bolt body 32 via the washer 33, and further lifting is restricted. At this time, the mounting bolt body 32 guides the fixed scroll 12 to secure a stable operation of the fixed scroll 12.

Next, the sealing structure for the high-pressure chamber 22 and its operation will be described in detail. As described above, an upper boss portion 12c is integrally formed on the fixed scroll end plate portion 12a, and a hooking projection 17 integrally formed on a back pressure plate 18 is inserted into the upper boss portion 12c. It is on the street.

A groove 35 having a rectangular cross section is provided along the outer peripheral surface of the leading end of the engaging projection 17, and the seal ring 16 serving as the seal member is inserted into the groove 35. FIG. 3 (A),
(B) shows the seal ring 16. The seal ring 16 has a rectangular cross section, and a part thereof is integrally connected via a connecting portion 16a which is a cut, and can be displaced in the circumferential direction. Therefore, the diameter of the seal ring 16 can be enlarged and changed within a predetermined range.

As shown in FIG. 2, the diameter of the high-pressure chamber 22 which is the inner diameter of the upper boss portion 12c and the outer diameter of the engaging projection 17 have only a small clearance k. The high-pressure gas filled in the sealing member 16 is guided.
Push up.

Further, from the lower end of the engaging projection 17 to the concave groove 35, a notch 36 serving as a gas pressure acting portion is provided.
Is provided. The cutouts 36 are provided at a plurality of locations at predetermined intervals in the circumferential direction of the hooking projection 17, and serve to supply high-pressure gas guided from the high-pressure chamber 22 through the discharge gas guide holes 17 a of the hooking projection 17. It is guided into the concave groove 35.

Accordingly, the seal ring 1 in the concave groove 35
6, the gas pressure guided along the clearance k between the upper boss 12c and the engaging projection 17 and the notch 3
6 and the gas pressure guided to 6.

As a result, the synthetic force direction of the force for pushing up the seal ring 16 along the axial direction and the force for expanding the seal ring 16 in the radial direction perpendicular to the axial direction, that is, the seal ring 16 Urges obliquely upward.

In this way, even when the compressor is started, the seal ring 16 quickly moves so as to be in close contact with the inner peripheral surface of the upper boss portion 12c and the upper surface of the concave groove 35, and contacts the high pressure side of the high pressure chamber 22. The sealing with the low-pressure side, which is the space M below the back plate 18, is reliably performed.

When the operation is shifted to the steady operation, the fixed scroll 1
2 is exercising with very small fluctuations,
Due to the influence, it is inevitable that a very small leak occurs in the seal ring 16 portion.

However, since the flow of the leaked gas coincides with the direction in which the seal ring 16 is pressed toward the seal surface,
It works in the direction of effectively reducing leakage. That is, the leakage can be changed to a negligible level.

FIGS. 4 and 5 show the fixed scroll 12A.
The above-described concave groove 35 is formed in the engaging projection 17 on the back pressure plate 18 side as a back pressure applying mechanism 14A for applying a back pressure to
A high-pressure chamber 22 is provided to guide the compressed high-pressure gas to the high-pressure chamber 22 and apply back pressure to fix the seal ring 16 to the fixed scroll head 1.
Instead of pressing and closely contacting the upper boss portion 12c on the back side of 2a, a concave groove 35 is formed in the upper boss portion 12c and the auxiliary upper boss portion 12d on the back side of the fixed scroll end plate portion 12a. A configuration in which an intermediate pressure chamber 40 is provided to apply a high-pressure gas after compression and an intermediate pressure to press the seal ring 16 against the engaging protrusion 17 and the auxiliary engaging protrusion 17A of the back pressure plate 18A to bring them into close contact is shown.

In particular, FIG. 4 schematically shows only the fixed scroll 12A and the back pressure plate 18A which are a part of the scroll compressor, but has basically the same configuration as described above. The gas pressure acting portion for guiding the high-pressure gas from the high-pressure chamber 22 into the groove 35 is formed by a drill hole 3 provided along the axial direction into the groove 35 from the upper end of the upper boss portion 12c of the fixed scroll end plate portion 12a.
6A.

An auxiliary upper boss portion 12d is integrally formed on the fixed scroll end plate portion 12a at a predetermined interval around the outer periphery of the upper boss portion 12c. And the back pressure plate 18A
Has an auxiliary engaging portion 17A engaging with the auxiliary upper boss portion 12d.
, And the seal ring 16 described above is interposed between them.

Therefore, a space is formed between the upper boss portion 12c and the auxiliary upper boss portion 12d, and the inner and outer peripheral surfaces are sealed by the seal ring 16. In addition, an intermediate pressure introducing hole 37 is provided at a part of the bottom surface of the space portion, which is an intermediate pressure guide portion that penetrates through the fixed scroll end plate portion 12a and communicates with the compression space S to guide the gas during compression. For this reason, the space is referred to as an intermediate pressure chamber 40.

The above-described seal ring 16 is provided on the inner peripheral side of the intermediate pressure chamber 40, and seals the high pressure side and the intermediate pressure side. A seal ring 16 is also provided on the outer peripheral side of the intermediate pressure chamber 40 to seal between the intermediate pressure side and the low pressure side.

With such a configuration, the high-pressure chamber 22 is formed at the center of the fixed scroll end plate 12a to apply a high-pressure back pressure, and the intermediate-pressure chamber 40 is formed around the high-pressure chamber 22 to form the intermediate-pressure back pressure. Pressure is applied.

The back pressure on the fixed scroll 12 does not concentrate in one place, and the back pressure is balanced from the center to the periphery, and the displacement of the fixed scroll 12 during the steady operation is almost the same. Absorbed.

As shown particularly in FIG. 5, a part of the compressed high-pressure gas is guided into the concave groove 35 through the drill hole 36A, while the clearance k between the upper boss 12c and the engaging projection 17 is increased. A part of the high-pressure gas is led into the concave groove 35 through
In either case, the seal ring 16 is pressed and urged.

Therefore, the seal ring 1 in the concave groove 35
6, the gas pressure guided along the clearance k between the upper boss portion 12c and the engaging projection 17 and the drill hole 3
And the gas pressure guided along 6A.

As a result, the direction of the combined force of the force for pushing down the seal ring 16 along the axial direction and the force for radially expanding the seal ring 16 which is the direction perpendicular to the axial direction, ie, the seal ring 16 As a force to push diagonally downward, and is urged to obtain a reliable sealing effect.

The clearance between the peripheral surface of the high-pressure chamber 22 and the peripheral surface of the fixed scroll 12, that is, the clearance between the outer peripheral surface of the upper boss portion 12c and the inner peripheral surface of the engaging projection 17 is L.
Assuming that the clearance between the two peripheral surfaces and the peripheral surface of the fixed scroll 12, that is, the clearance between the upper surface of the concave groove 16 and the upper surface of the seal ring 16 is c, L is set to be larger than c (L> c).

Therefore, the amount of gas flowing toward the clearance L becomes larger than the amount of gas flowing toward the clearance c, and the sealing ring 16 is pressed and urged with a stronger force to ensure a sealing effect.

The above description is also applied to the clearance between the auxiliary upper boss 12d and the auxiliary engaging projection 17A and the sealing structure for the intermediate pressure chamber 38, and the same operation and effect can be obtained here.

The scroll compressor is not necessarily limited to the one provided in the equipment constituting the refrigeration cycle, and can be used for compressing other types of compressed gas or air.

[0077]

As described above, according to the first to seventh aspects of the present invention, in addition to having a so-called compliance function for supporting the fixed scroll so as to be freely movable in the axial direction, it is also possible to provide a function at the time of starting the compressor. Even during normal operation, a reliable sealing effect is obtained, and the effect of improving compression performance and reliability is achieved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view, partially omitted, of a scroll compressor according to an embodiment of the present invention.

FIG. 2 is a view showing the embodiment and illustrating a sealing action.

FIG. 3A is a perspective view of a seal ring according to the embodiment. (B) is a figure which cuts out one part and shows it in an enlarged manner.

FIG. 4 is a partial cross-sectional view of a compression mechanism, showing another embodiment.

FIG. 5 is a view showing the embodiment and illustrating a sealing action.

FIG. 6 is a cross-sectional view of a conventional scroll compressor in which a part is omitted.

FIG. 7 is a partially omitted cross-sectional view of another conventional scroll compressor.

FIG. 8 is a view for explaining a sealing action in the scroll compressor of FIG. 6;

[Description of Signs] 12 ... fixed scroll, 12b ... (fixed scroll) wings, 12a ... (fixed scroll) end plate, 11 ... orbiting scroll, 11b ... (orbiting scroll) wings, 11a ... (orbiting scroll) ) End plate portion, S: compression space, 13: mounting member, 14: back pressure applying mechanism, 16: seal member (seal ring), 36: gas pressure acting portion (notch portion), 22: high pressure chamber, 15: discharge Pressure guide (discharge port), 35: concave groove, 40: intermediate pressure chamber, 37: intermediate pressure guide (intermediate pressure introduction hole), 36A: drill hole.

Claims (7)

[Claims] 1. A scroll type compressor in which a wing portion of a fixed scroll and a wing portion of an orbiting scroll are meshed with each other to form a compression space with the wing portion, a fixed scroll and a head plate of the orbiting scroll. An attachment member for movably attaching the fixed scroll in the axial direction, and gas pressure is applied to the back side of the fixed scroll to apply a back pressure to the fixed scroll during normal operation to regulate axial movement and abnormally increase the pressure in the compression space. Occasionally, a back pressure applying mechanism that allows the fixed scroll to move in the axial direction to widen the clearance with the orbiting scroll to allow gas in the compression space to escape, and the back pressure by this back pressure applying mechanism is sealed on the back side of the fixed scroll. The gas pressure is guided in the direction of the resultant force in the axial direction and the direction perpendicular to the axial direction with respect to the seal member to be pressed, and the seal member is pushed. A scroll-type compressor comprising: a gas-pressure operating section for urging the pressure. 2. The back pressure applying mechanism includes: a back pressure chamber formed by a fixed scroll end plate rear side and a back pressure plate; and a high-pressure gas that has been compressed from a compression space is introduced into the back pressure chamber to form the back pressure chamber. A discharge pressure guide portion for increasing the pressure, wherein the seal member is a seal ring movably housed in a concave groove provided along the periphery of the back pressure chamber and expandable in the radial direction. 2. The scroll compressor according to claim 1, wherein the gas pressure acting portion is a notch for guiding the gas pressure so as to press the seal ring obliquely against the peripheral surface of the back pressure chamber. . 3. The back pressure applying mechanism includes a first back pressure chamber and a second back pressure chamber formed on the back side of the fixed scroll end plate, and a gas that has been compressed into the first back pressure chamber. A discharge pressure guide portion for guiding the discharge pressure to a discharge pressure, and an intermediate pressure guide portion for guiding the gas under compression from the compression space to the second back pressure chamber to make the second back pressure chamber an intermediate pressure, 2. The scroll compressor according to claim 1, wherein the seal member and the gas pressure acting portion are provided on at least one of the intermediate pressure guide portion and the discharge pressure guide portion. 4. The scroll according to claim 2, wherein the concave groove is formed on the back side of the fixed scroll end plate portion, and the seal ring is pressed against the back pressure plate to be in close contact therewith. Type compressor. 5. The scroll system according to claim 2, wherein said concave groove is formed in said back pressure plate, and said seal ring is pressed against and close to the back side of said fixed scroll head. Compressor. 6. The scroll-type compressor according to claim 4, wherein said gas pressure acting portion is a drill hole provided in the fixed scroll along the axial direction. 7. The following conditions are established, where c is a gap in the direction perpendicular to the axial direction of the side surface of the seal ring and the groove, and L is the clearance between the peripheral surface of the back pressure chamber and the peripheral surface of the fixed scroll. The scroll type compressor according to claim 2, wherein c <L