JP2790125B2 - Scroll gas compressor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the application of back pressure to a non-compression chamber side of an orbiting scroll in a scroll gas compressor.

[0002]

2. Description of the Related Art In a scroll compressor having low vibration and low noise characteristics, a suction chamber is provided at an outer peripheral portion, a discharge port is provided at a central portion of a spiral, and a flow of a compressed fluid is reciprocated in one direction. It does not require a discharge valve for compressing fluid like a compressor or rotary compressor, has a constant compression ratio, has a small discharge pulsation, and does not require a large discharge space. Chemical research is being conducted.

However, since there are many seal portions in the compression chamber, there is a lot of leakage of the compressed fluid. Particularly, in the case of a scroll gas compressor having a small displacement capacity such as a refrigerant compressor for home air conditioning,
In order to reduce the leakage gap of the compression part, it is necessary to make the dimensional accuracy of the spiral part extremely high.

[0004] However, the cost of the scroll gas compressor is high and the performance of the scroll gas compressor is large due to the complicated shape of the parts and the variation in the dimensional accuracy of the spiral part. In particular, when the compressor is operated at a low speed, the gas leakage rate during compression is large. However, it has a disadvantage that the compression efficiency is lower than that of a reciprocating compressor or a rotary compressor.

Therefore, as a measure for solving this kind of problem, it is desired to optimize the spiral part dimensional accuracy and improve the compression efficiency by an oil film sealing effect using a lubricating oil to prevent gas leakage during compression. Largely, as described in JP-A-57-8386, an appropriate amount of lubricating oil is injected into the compression chamber in the middle of compression, the gap between the compression chambers is sealed with an oil film of the lubricating oil, and the above-mentioned disadvantages are improved. A proposal has been made.

In particular, scroll refrigerant compressors have been put into practical use in the field of refrigeration and air conditioning, and various types of medium- to large-sized compressors such as packaged air conditioners and chiller units, which have a relatively large refrigerant capacity per one suction process, have been developed. Improvements have been made and mass production has already been realized.

FIG. 16 shows an example of the structure of a medium to large class scroll refrigerant compressor having a high-pressure space inside a sealed case. The figure shows a configuration in which the compression mechanism is located at the top, the motor is located at the bottom, the oil sump is located at the bottom, and the discharge pipe, which is the final outlet of the compressor, is located near the motor. On the back side, a large back pressure area 1450 on which the discharge pressure acts is provided, while a low pressure area 1451 is provided on the outer periphery thereof.
In order to form the back pressure region 1450, the back surface of the orbiting scroll 1424 is slidably sealed with an annular thrust seal 1449 fixed to the frame 1413 and having a large back pressure biasing area, and the orbiting scroll 1424 is fixed. Scroll 1426
Orbiting scroll 1424 and fixed scroll 14
Do not separate from 26. In addition, the lubricating oil at the bottom of the sealed case is decompressed through the small tube, and is supplied with a differential pressure between the outer peripheral portion of the orbiting scroll 1424 and the sliding contact surface of the fixed scroll 1426. To seal the compression chamber gap with the oil film.

Further, a high-pressure lubricating oil at the bottom of the sealed case is pumped up by a centrifugal pump action by an oil passage (not shown) provided in the drive shaft 1417, and an annular thrust seal 1449 passes through a bearing portion of the drive shaft 1417. And then return to the bottom of the closed case again after refueling inside. (US Patent No.
No. 4522575).

[0009]

However, in the above configuration, since the orbiting scroll 1424 makes an orbiting motion, the center of the back pressure urging surface to the orbiting scroll 1424 and the orbiting scroll
The center of the drive short axis 1424a, which is the center of the downward thrust force acting on 1424 [generally, in order to reduce the inclination of the orbiting scroll due to the compression pressure, the center of the compression chamber and the axis of the orbiting scroll (the driving short axis) Often coincide with the center of the axis 1424a) or separated by only a small distance.]
And consistently, orbiting scroll 1424
The center of the back pressure biasing surface moves. As a result, the direction in which the orbiting scroll 1424 is inclined between the downward thrust force acting on the orbiting scroll 1424 due to the liquid compression in the compression chamber and the upward discharge back pressure acting on the back surface of the orbiting scroll 1424 An alternating overturning moment occurs. This allows instantaneous orbiting scroll 1424 and fixed scrolling
Axial gap and fall between 1426 and 1426 cause compression performance to deteriorate, and the orbiting scroll 1424 and the fixed scroll 14
Generation of abnormal noise and orbiting scroll 1424 due to collision with 26
Drive shaft and orbiting scroll 1424 drive short axis 1424
There has been a problem that the durability is reduced due to the one-side contact phenomenon of the connection bearing portion with the connection bearing a.

The present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide a back pressure chamber structure capable of constantly biasing the center of the orbiting scroll with back pressure.

[0011]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is directed to a sealing section which includes a bearing portion which communicates with a high pressure side oil reservoir relating to a drive shaft and a back pressure chamber of an orbiting scroll provided on an outer peripheral portion thereof. For this purpose, an annular ring which is arranged between the main frame supporting the drive shaft and the orbiting scroll and surrounds the drive shaft, and is movably mounted on the orbiting scroll, has its center substantially coincident with the center of the orbiting scroll. It is arranged in. The orbiting scroll always receives the back pressure biasing force at the center thereof, and can always slide and contact the fixed scroll to maintain the compression chamber gap minutely without receiving the action of the overturning moment.

[0012]

According to a first aspect of the present invention, there is provided a main frame supporting a drive shaft provided with a main bearing close to the orbiting scroll, while imparting a orbiting motion to the orbiting scroll. A swivel bearing portion for slidably coupling between the drive shaft and the orbiting scroll is provided on the lap support disk of the orbiting scroll, and discharge pressure acts on the main bearing through an oil reservoir disposed in the closed case. Between the main body frame and the orbiting scroll, an annular ring defining an oil chamber communicating with the orbiting bearing portion and a back pressure chamber provided outside the oil chamber and on the side of the orbiting scroll opposite to the compression chamber. And the annular ring is mounted on the orbiting scroll so that the center of the annular ring substantially coincides with the center of the orbiting scroll. As a result, the high-pressure back pressure chamber of the orbiting scroll follows the orbiting movement of the orbiting scroll and constantly urges the back pressure to the center of the orbiting scroll while moving orbiting, thereby preventing the orbiting scroll from tilting with respect to the fixed scroll. Can be prevented.

According to a second aspect of the present invention, the annular ring is arranged in an annular seal groove provided in a swivel bearing boss portion constituting a swivel bearing portion provided to protrude from the lap support disk. Thus, the annular ring can be provided without reducing the rigidity of the lap support disk.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A scroll refrigerant compressor according to a first embodiment of the present invention will be described below with reference to FIGS.

In FIG. 1, reference numeral 1 denotes a closed case made of iron.
The interior is meshed with the orbiting scroll 18 to fix the fixed scroll 15 forming a compression chamber with bolts, and is partitioned into the upper motor chamber 6 and the lower accumulator chamber 46 by the main body frame 5 supporting the drive shaft 4. I have.

The motor chamber 6 is in a high-pressure atmosphere. The main body frame 5 supporting the drive shaft 4 in which the motor 3 is arranged at the upper part and the compression part is arranged at the lower part, and the rotor 3a of the motor 3 is connected and fixed, has sliding characteristics and welding. It is made of eutectic graphite cast iron having excellent heat resistance, and the projections 79a provided on the outer peripheral surface thereof are in contact with the inner wall surfaces and the end surfaces of the upper sealed case 1a and the lower sealed case 1b.
a, the upper sealed case 1a and the lower sealed case 1b are hermetically welded by a single welding bead 79b.

The drive shaft 4 has an upper bearing 11 provided at the upper end of the main body frame 5, a main bearing 12 provided at the center, and a plurality of radial shallow grooves 7 provided at the upper end face of the main body frame 5. The crankshaft 14 at the lower end, which is supported by the thrust bearing 13 and is eccentric from the main shaft of the drive shaft 4, is engaged with the orbiting bearing 18b of the orbiting boss 18e provided on the orbiting scroll 18.

The fixed scroll 15 is made of a high silicon aluminum alloy whose coefficient of thermal expansion is equivalent to an intermediate value between pure aluminum and eutectic graphite cast iron, and has a spiral fixed scroll wrap 15a as shown in FIG. 15b, end plate 15
At the center of the fixed scroll wrap 15a, a discharge port 16 that opens at the beginning of the winding of the fixed scroll wrap 15a is provided in communication with a discharge passage 80 that opens to the motor chamber 6, and at the outer periphery of the fixed scroll wrap 15a, a suction chamber 17 is provided. Is provided.

A check valve device 50 is mounted on the end plate 15b on the side opposite to the orbiting scroll so as to cover the discharge port 16.
The check valve device 50 is a valve body made of a thin steel plate whose outer peripheral portion is cut out at several places, as will be described in detail with reference to FIGS.
50b (or valve element 50e having discontinuous annular hole 50ea)
A valve case 99 having a check valve hole 50a, a central hole 50g, and a plurality of small discharge holes 50h therearound; a valve body 50b and a valve case 99.
And a spring device 50c interposed therebetween. Spring device 50
c has a shape memory characteristic of contracting when its own temperature exceeds 50 ° C. and elongating at its own temperature of 50 ° C. or less. hole
The valve body shrinks to the bottom of 50a, and its own temperature is below 50 ° C.
50 is set to be pressed against the end plate 15b.

As shown in FIGS. 1 and 14, a spiral scroll wrap 18a meshing with the fixed scroll wrap 15a to form a compression chamber side wall, and a rotary boss 18e engaged with the crankshaft 14 of the drive shaft 4. The orbiting scroll 18 made of an aluminum alloy, which is composed of a wrap supporting disk 18c having a vertical upright, is disposed so as to be surrounded by the fixed scroll 15 and the main body frame 5. The surfaces of the wrap supporting disk 18c and the orbiting scroll wrap 18a are porous. Hardening treatment such as high quality nickel plating is performed. As shown in FIG. 3, a spiral tip seal groove is provided at the tip of the orbiting scroll wrap 18a.
A chip seal 98a made of resin is mounted in the chip seal groove 98 with a minute gap. When the orbiting scroll 18 is pressed in the axial direction of the fixed scroll 15, the flat portion of the wrap support disk 18c contacts the tip of the fixed scroll wrap 15a.
The tip of 18a keeps a minute distance of about several microns without touching the fixed scroll 15.

The discharge passage 80 (see FIG. 1) is connected to the check valve device 50.
Cover 2a mounted on end plate 15b to cover
The discharge guide 81 attached to the main body frame 5 so as to surround the gas passage B 80 b provided in the fixed scroll 15, the gas passage A 80 a provided in the main body frame 5, and the main bearing 12. And a discharge chamber 2b formed by the main body frame 5, and the gas passage A80a and the gas passage B80b are respectively provided at target positions (see FIG. 14).

As shown in FIG. 7, a large number of small holes 81a are provided on the upper surface of the discharge guide 81. The accumulator chamber 46 leading to the evaporator side of the refrigeration cycle has a lower sealed case 1
b, the fixed scroll 15 and the body frame 5,
A suction pipe 47 communicating with the suction pipe 47 is provided on a side surface of the lower sealed case 1b, and is approximately 9
The suction holes 43 are fixed at two positions separated by 0 degrees.
(See FIG. 14).

The low-pressure oil reservoir 46 at the bottom of the accumulator chamber 46
a and the suction hole 43 communicate with an oil suction hole A9a provided in the discharge cover 2a and a small-diameter oil suction hole B9b provided in the fixed scroll 15, and these oil suction holes (9a, 9a,
9b) is set so that the refrigerant liquid or the lubricating oil retained in the low-pressure oil reservoir 46a is sucked up by generation of a negative pressure when the refrigerant gas passes through the suction hole 43.

The plate-shaped thrust bearing 20, which is restricted in movement in the rotational direction by a split pin-shaped parallel pin 19 fixed to the main body frame 5 and can move only in the axial direction, comprises a lap support disk 18c and the main body frame 5 Between the main frame 5 and the fixed scroll 15 by the elastic force of an annular seal ring (made of rubber) 70 (see FIG. 10) interposed between the thrust bearing 20 and the main frame 5. Is in contact with the end plate mounting surface 15b1.

The height from the end plate sliding surface 15b2 to the end plate mounting surface 15b1 which is in sliding contact with the lap support disk 18c of the orbiting scroll 18 is determined by the lap support disk 18c in order to improve the sealing property of the sliding portion by the oil film of the lap support disk 18c. About 0.01 than the thickness of 18c
5 to 0.020mm is set larger.

As shown in FIGS. 1 and 8, the orbiting scroll
An annular seal groove 95 concentric with the center of the swivel bearing 18b is provided on the end face of the swivel boss 18e on the body frame 5 side, and a part of the annular seal groove 95 as shown in FIG. A cut annular resin ring 94 having flexibility is mounted. The outer peripheral surface of the annular ring 94 is disposed so as to be in close contact with the side surface of the annular seal groove 95 due to thermal expansion of the annular ring 94 and lubricating oil pressure inside the annular ring 94 during operation of the compressor. The annular ring 94 is excessively connected to the back pressure chamber 39 of the orbiting scroll 18 formed by the orbiting scroll 18, the body frame 5 and the thrust bearing 20 from the oil chamber A 98 a on the side of the main bearing 12 that supports the drive shaft 4. Sealed to prevent lubricant leakage.

The annular thrust bearing 20 is made of a sintered alloy whose hole can be easily formed. As shown in FIGS. 10 and 11, two guide holes 93 into which the split pins 19 are movably inserted, an annular oil groove 92, and an oil It has a hole 91 and is mounted in the thrust ring groove 90 of the main body frame 5.

A release gap 27 of about 0.05 mm is provided between the main frame 5 and the thrust bearing 20, and an annular groove 28 for mounting a seal ring 70 is provided inside and outside the release gap 27. . Seal ring 70 is the release gap
The space between 27 and the back pressure chamber 39 is sealed.

The release gap 27 is formed by the third compression chamber 60b (FIG. 14) in the final compression stroke by the thrust back pressure introducing hole A89a provided in the main body frame 5 and the thrust back pressure introducing hole B89b provided in the fixed scroll 15. See also).

As shown in FIGS. 1 and 2, the thrust bearing 20
The anti-rotation member (hereinafter referred to as Oldham ring) 24 of the orbiting scroll 18 disposed on the inside of the flat ring is made of a light alloy or a reinforcing fiber composite material suitable for sinter molding or injection molding, etc. The key portion on the upper surface side is provided with a key groove 71a provided on the main body frame 5, and the key portion on the lower surface side is provided with a key groove provided on the lap support disk 18c. Engage with 71 and slide.

The thickness of the Oldham ring 24 is set such that the Oldham ring 24 slides smoothly between the main frame 5 and the lap support disk 18c and does not cause a jumping phenomenon when the Oldham ring 24 reciprocates. I have.

A discharge pipe 31 is mounted on the outer peripheral portion of the upper end wall of the upper sealed case 1a, and a glass terminal 88 for connecting a motor power supply is mounted on a central portion.

An oil separator 87 attached to the upper sealed case 1a separates the side of the discharge pipe 31 and the glass terminal 88 from the side of the motor 3. The rotor 3a of the motor 3 axially positioned by the stepped portion of the drive shaft 4 is bolted to the drive shaft 4 together with the upper balance weight 75,
The upper balance weight 75 has a disk shape, and its outer diameter is set to be larger than the outer diameter of the rotor 3a.

Between the lower balance weight 76 attached to the lower end of the rotor 3a and the discharge guide 81, a shielding plate 86 attached to the main frame 5 is arranged close to the lower balance weight.

A discharge chamber oil sump provided below the motor chamber 6
34 is connected to the upper part of the motor chamber 6 by a cooling passage 35 provided by cutting out a part of the outer periphery of the stator 3b of the motor 3.

The discharge chamber oil reservoir 34 is connected to the main bearing 12 and the slewing bearing 18b through an oil hole A38a provided in the main body frame 5.
The oil chamber A78a is located at an intermediate position between the two.

As shown in FIGS. 1 and 8, the lubricating oil in the oil chamber A78a is provided on the surface of the sliding shaft portion 4a of the drive shaft 4 and the surface of the crankshaft 14 when the drive shaft 4 rotates forward. Helical oil grooves 41a and 41b are provided in the oil chamber B78b formed by the oil pump B and the crankshaft 14 in the direction in which the screw pump oil is supplied to the motor 3, and the upper end thereof reaches the thrust bearing portion 13.

The oil chamber B78b and the surface of the main bearing 12 are communicated with each other by an oil supply hole 73a provided in the drive shaft 4, and the oil sump 72 between the upper bearing 11 and the main bearing 12 and the back pressure chamber 39 are connected to the main body frame. 5
The oil hole B38b having a throttle passage portion provided in the oil hole B38b communicates with the annular pressure ring.
The opening is intermittently opened to a discontinuous oil groove 94a provided at the center and is opened and closed by an annular ring 94 intermittently.

As shown in FIGS. 1, 10, and 14, the back pressure chamber
39 is a first compression chamber 61a, 61b intermittently communicating with the suction chamber 17.
The oil hole 91 provided in the thrust bearing 20, the outer peripheral space 37 outside the lap support disk 18c, and the wrap support disk 18 are within a rotation angle range of about 180 degrees before the suction refrigerant gas is completely confined.
c, and is communicated with the first compression chambers 61a, 61b by an injection passage 74 constituted by an oil hole C38c provided at the symmetric position and small-diameter injection holes 52a, 52b. The oil hole 91 is opened and closed intermittently by the lap support disk 18c.

As shown in FIG. 12 and FIG.
A back pressure control valve device 25 for controlling the pressure of the back pressure chamber 39 is mounted on 18c.

The back pressure control valve device 25 includes a lap support disk 18c.
A stepped cylinder 26, which is provided in the radial direction of the cylinder and includes a large diameter cylinder 26a and a small diameter cylinder 26b, a stepped plunger 29 movable in the cylinder, and an outer peripheral space 37 side of the cylinder 26 Cap to close part of open end
32, a coil spring disposed between the cap 32 and the plunger 29 to urge the plunger 29 toward the crankshaft 14
53, an oil hole 54a communicating the crankshaft 14 side of the large diameter cylinder 26a with the suction chamber 17, and a crankshaft of the small diameter cylinder 26b.
It is constituted by oil holes 54b and 54c which communicate the 14 side with the oil chamber B 78b and the back pressure chamber 39, respectively. Its operation is
When the pressure in the back pressure chamber 39 is within an appropriate range, as shown in FIG. 12, when the small-diameter end surface of the plunger 29 closes the cylinder-side opening end of the oil hole 54b, and when the pressure in the back pressure chamber 39 is insufficient, as shown in FIG. As shown in the figure, the plunger with the large diameter part of the plunger 29 as the boundary
The plunger 29 moves toward the outer peripheral space 37 due to the biasing force difference acting on both sides of the cylinder 29, the cylinder-side opening end of the oil hole 54b is opened, and the coil spring 53 is moved so that the oil chamber B78b and the back pressure chamber 39 communicate with each other. And the dimensions of each part of the cylinder 26 are set.

Reference numeral 55 denotes an O-ring mounted on the small-diameter portion cylinder 26b for sealing the small-diameter outer peripheral portion of the plunger 29.

In FIG. 15, the horizontal axis indicates the rotation angle of the drive shaft 4, the vertical axis indicates the refrigerant pressure, the pressure change state of the refrigerant gas during the suction, compression, and discharge processes, and the solid line 62 indicates the normal pressure. The dotted line 63 shows the pressure change when the abnormal pressure rises.

The operation of the scroll refrigerant compressor configured as described above will be described.

1 to 16, when the drive shaft 4 is driven to rotate by the motor 3, the orbiting scroll 18 tries to rotate around the main shaft of the drive shaft 4 by the crank mechanism of the drive shaft 4. The key portion (see FIG. 2) on the side of the orbiting scroll 18 is a keyway 71 of the orbiting scroll 18.
And the key portion on the opposite side is the key groove 71 of the main body frame 5.
a (see FIG. 1), the rotation is prevented, the orbital motion is made, and the volume of the compression chamber is changed together with the fixed scroll 15 to perform the suction / compression operation of the refrigerant gas.

Then, from the refrigerating cycle connected to the compressor, the suction refrigerant of the gas-liquid mixture containing the lubricating oil flows from the suction pipe 47 into the accumulator chamber 46 and collides with the outer surface of the end plate 15b of the fixed scroll 15 after the collision. Then, the air flows into the suction chamber 17 through two suction holes 43 (see FIG. 14) through the upper space of the accumulator chamber 46.

On the other hand, the liquid refrigerant and the lubricating oil separated from the refrigerant gas by the weight difference between the gas and the liquid and the inertia force at the time of changing the flowing direction are once collected at the bottom of the accumulator chamber 46,
Due to the negative pressure generated when the suction refrigerant gas passes through the suction hole 43, the suction refrigerant gas is sucked up into the suction hole 43 in an atomized state through the oil suction holes A9a and B9b, and is mixed into the suction refrigerant gas again.

The suction refrigerant gas separated into gas and liquid is supplied to the suction chamber 1
7. It is confined in the compression chamber through the first compression chambers 61a and 61b (see FIG. 14) formed between the orbiting scroll 18 and the fixed scroll 15, and the second compression chambers 51a and 51b and the third compression chamber 60a,
After being sequentially transferred and compressed to 60b, it is discharged from the central discharge port 16 to the check valve chamber 50a, and then to the motor chamber 6 via the discharge chamber 2, the gas passage B80b, the gas passage A80a, and the discharge chamber 2b in order. Discharged.

When the third compression chambers 60a and 60b and the discharge port 16 are opened immediately after the completion of the compression, the compressed refrigerant gas becomes
A sudden primary expansion occurs when flowing into the check valve chamber 50a from the third compression chambers 60a, 60b, and the refrigerant gas discharged from the check valve chamber 50a becomes primary during a period from immediately after the discharge completion stroke to the compression start stroke. The gas flows backward to the third compression chambers 60a and 60b.

As a result, the refrigerant gas intermittently flows out of the third compression chamber (60a, 60b).
b) while repeating the flow into
The refrigerant gas flows out from the compression chambers (60a, 60b) to the discharge chamber 2, but the refrigerant gas discharged from the check valve chamber 50a and the discharge chamber 2 is discharged to the third compression chamber (60a, 60b).
a, 60b) causes a pressure fluctuation at the time of inflow / outflow to the pulsation phenomenon.

The pulsation of the discharged refrigerant gas causes secondary expansion when flowing into the discharge chamber 2 having a spherical wall surface through the small discharge hole 50h of the check valve device 50, and furthermore, the secondary pulsation provided at the symmetrical position. When the two discharge passages 80 merge in the discharge chamber 2b and the motor chamber 6, the discharge gas pulsations from the discharge passages 80 attenuate each other, and further attenuate sequentially by the third and fourth expansions. The pressure in the motor chamber 6 hardly fluctuates.

When the discharged refrigerant gas instantaneously flows backward from the discharge chamber 2 to the check valve chamber 50a, the valve body 5 follows the flow.
0b tries to move in a direction to close the discharge port 16, but during the operation of the compressor, the coil spring 50c having shape memory characteristics is completely contracted due to the ambient temperature and does not exert a bias on the valve body 50b, and the magnetic force is reduced. Since the valve body 50b with the pressure is adsorbed on the bottom surface of the check valve chamber 50a and does not separate, the valve body 50b does not block the discharge port 16.

The refrigerant gas discharged from the small holes 81a of the discharge guide 81 and discharged into the motor chamber 6 collides with the annular closing plate 86 and the windings of the motor 3, and then the cooling passage 35 on the outer side of the stator 3b. It flows to the upper side of the motor chamber 6 while cooling the motor 3 through the inner and inner passages, and is sent from the discharge pipe 31 to an external refrigeration cycle.

At this time, part of the lubricating oil in the discharged refrigerant gas adheres to the surface of the lower winding of the motor 3 and is separated from the refrigerant gas and collected in the discharge chamber oil reservoir 34. The lubricating oil in the discharged refrigerant gas passing through the outer periphery of the weight 75 and the lower balance weight 76 is supplied to the upper balance weight 7
5. Centrifuged by rotation of the lower balance weight 76, diffused to the inner surface of the winding of the motor 3, flows down along the internal space of the winding bundle, and is collected in the discharge chamber oil reservoir 34.

The release gap 27 on the back side of the thrust bearing 20 which communicates with the compression chamber in the final compression stroke (the compression space immediately before the compression chamber communicates with the discharge port 16) is filled with high-pressure refrigerant gas as time elapses after the start of compression. Is done. The thrust bearing 20 is pressed against the end plate mounting surface 15b1 of the fixed scroll 15 by the back pressure urging and the elastic force of the seal ring 70. As a result, the lap support disk 18c of the orbiting scroll 18 is held between the end plate sliding surface 15b2 and the thrust bearing 20 (15 to 2).
0 micron assembly gap).

The lubricating oil in the discharge chamber oil reservoir 34 flows into the oil chamber A 78a, the oil chamber B 78b, and the back pressure chamber 39 via a path described later.
The back pressure applying force to the orbiting scroll 18 gradually increases.
Following the pressure increase of the motor chamber 6, the lap support disk 18c
Gradually comes into contact with the end plate sliding surface 15b2 of the fixed scroll 15 with an appropriate pressing force. There is no gap between the tip of the fixed scroll wrap 15a and the wrap support disk 18c of the orbiting scroll 18, whereby the compression chamber is sealed, the suction refrigerant gas is efficiently compressed, and stable operation is continued.

The gap in the axial direction between the end of the orbiting scroll wrap 18a and the end plate 15b of the fixed scroll 15 is formed when the refrigerant gas during compression leaks to the adjacent low-pressure side compression chamber.
The gas flows into the chip seal groove 98 (see FIG. 3), and is sealed by being pressed by the gas back pressure against the side of the low compression chamber of the chip seal groove 98a and the end plate 15b of the fixed scroll 15.

When the compressor is stopped, the orbiting scroll 18 instantaneously makes a reverse orbital motion due to the backflow based on the pressure difference of the refrigerant gas in the compression chamber. However, since the refrigerant gas flows back from the compression chamber to the suction chamber 17, The orbiting scroll 18 is as shown in FIG.
The first compression chambers 61a and 61b stop at the turning angle in a state where they communicate with the suction chamber 17. As shown in FIG. 8, in this stopped state, the annular ring 94 closes the lubricating oil inlet to the back pressure chamber 39.

When the compressor is stopped, the refrigerant gas in the compression chamber flows back to the suction chamber 17 so that the refrigerant gas pressure at the discharge port 16 drops sharply, and the refrigerant gas pressure difference between the discharge port 16 and the discharge chamber 2 increases. As a result, the valve body 50b closes the discharge port 16 and prevents continuous backflow of the discharged refrigerant gas from the discharge chamber 2 to the compression chamber.

Due to the temporary reverse flow of the discharged refrigerant gas immediately after the compressor is stopped and the reverse rotation of the orbiting scroll 18, the magnetic valve element 50b is separated from the bottom surface of the check valve chamber 50a, and the refrigeration cycle is pressure-balanced. Until the valve element 51
b keeps closing the discharge port 16. At the same time, the coil spring 50 having the shape memory characteristic lowers in temperature and expands, and the urging force of the coil spring 50 keeps the valve body 50b closing the discharge port 16.

The first compression chamber 61 intermittently communicating with the suction chamber 17
The a and 61b communicate with the back pressure chamber 39 via the oil hole 91 (see FIG. 10) provided in the thrust bearing 20 only when the first compression chambers 61a and 61b are within 180 degrees before the closing is completed. Along with
Since the space between the thrust bearing 20 and the lap support disk 18c is sealed by the lubricating oil film, the refrigerant gas does not flow backward from the compression chamber to the back pressure chamber 39 during compression.

When the compressor is stopped for a long time, the pressure in the compressor is balanced, and the liquid refrigerant flows into the accumulator chamber 46 as well as into the compression chamber. A thrust force in the direction opposite to the discharge port 16 acts on the orbiting scroll 18 by the pressure of the liquid compressed refrigerant in the compression chamber. As a result, the orbiting scroll 18 is separated from the fixed scroll 15 in the axial direction, and the compression load is reduced.

On the other hand, the pressure in the back pressure chamber 39 at the initial stage of the start of the cold operation of the compressor is substantially equivalent to the suction pressure because the pressure rise in the discharge chamber oil reservoir 34 is low. As a result, the lap support disk 18c of the orbiting scroll 18 is backed up from the end plate sliding surface 15b2 to the thrust bearing 20 in a state where the back pressure is applied only by the lubricating oil in the oil chamber A78a having a low pressure rise, A gap is formed between the lap support disk 18c and the tip of the fixed scroll wrap 15a, the compression chamber pressure is reduced, and the compression load at the beginning of startup is reduced.

In the event that liquid compression or the like occurs in the compression chamber and the pressure in the compression chamber rises abnormally instantaneously during continuous operation, the thrust force acting on the orbiting scroll 18 is applied to the back of the orbiting scroll 18. The orbiting scroll 18 moves in the axial direction, and the thrust bearing
Supported by 20. Then, the sealing of the compression chamber is released in the same manner as described above, the compression chamber pressure is reduced, and the compression load is reduced.

The back pressure chamber 39 includes first compression chambers 61a and 61b.
Communicates with the outer peripheral space 37 through the oil hole 91 provided in the thrust bearing 20 within a swirl angle range of about 180 degrees before the suction refrigerant gas is completely confined. Does not occur.

Therefore, in any compressor operating state including the occurrence of liquid compression in the compression chamber, the backflow of the refrigerant gas in the compression chamber to the back pressure chamber 39 is avoided, and the reduction of the compression load is not hindered.

The lubricating oil in the discharge chamber oil reservoir 34 at the early stage of the cold start of the compressor is supplied to the oil chamber A78a via the oil hole A38a by the screw pump action of the spiral oil grooves 41a and 41b provided on the drive shaft 4. Inhaled.

Thereafter, a part of the lubricating oil is supplied to the spiral oil grooves 41b, 41b.
The lubricating surface of the slewing bearing 18b is lubricated on the way through the oil chamber B78b and the oil supply hole 73a in order, and is supplied to the sliding surface of the main bearing 12 so that the oil sumps.
Sent to 72.

The lubricating oil supplied to the main bearing 12 by the helical oil groove 41a joins with the lubricating oil passing through the oil chamber B78b in the oil sump 72, and a part of the lubricating oil is turned into an oil hole B38b (FIG. 8). The pressure is reduced in the throttle passage section and the oil is intermittently supplied to the back pressure chamber 39, and the remaining lubricating oil is recovered in the discharge chamber oil reservoir 34 after lubricating the sliding surfaces of the upper bearing 11 and the thrust bearing section 13. Is done.

The refrigerant gas in the motor chamber 6 is supplied to the upper bearing
Lubricating oil passing through 11 prevents backflow to oil sump 72.

The pressure of the refrigerant gas discharged from the motor chamber 6 increases following the elapse of time after the start of the compressor in cold mode, and the lubricating oil in the oil chamber 34 of the discharge chamber is also oiled by the differential pressure between the back chamber 39 and the oil. The oil is sucked into the chamber A78a and supplied to the back pressure chamber 39 together with the screw pump action of the spiral oil grooves 41a and 41b. The pressure in the back pressure chamber 39 gradually increases, and a combined force with the lubricating oil pressure corresponding to the discharge pressure of the oil chamber A 78a acts on the lap support disk 18c of the orbiting scroll 18. As a result, the thrust load acting to separate the orbiting scroll 18 from the fixed scroll 15 is canceled by the refrigerant gas pressure in the compression chamber, and the thrust force acting on the orbiting scroll 18 is reduced.

Accordingly, while the pressure increase in the motor chamber 6 after the cold start of the compressor is low, the force exerted on the orbiting scroll 18 by the lubricating oil pressure in the oil chamber A 78a and the back pressure chamber 39 increases the refrigerant gas pressure in the compression chamber. Smaller than the thrust load on the orbiting scroll 18 due to As a result, the orbiting scroll 18 separates from the fixed scroll 15, and is supported by the thrust bearing 20 which receives the elastic force of the seal ring 70 and the back pressure due to the refrigerant gas introduced from the compression chamber in the final compression stroke.

When the pressure difference between the discharge pressure and the suction pressure exceeds the required pressure, the force applied to the orbiting scroll 18 by the lubricating oil pressure in the oil chamber A 78a and the back pressure chamber 39 causes the orbiting by the refrigerant gas pressure in the compression chamber. It becomes larger than the thrust load on the scroll 18. The orbiting scroll 18 is supported by the fixed scroll 15.

In an arrangement in which the center of the compression chamber, the center of the slewing bearing 18e, and the center of the annular ring 94 substantially coincide with each other,
Since the annular ring 94 orbits together with the orbiting scroll 18, the annular ring 94 tends to jump out of the annular seal groove 95 provided in the orbiting boss 18e by the inertial force at that time. Further, the annular ring 94 expands its inner diameter by the differential pressure between the oil chamber A 78a and the back pressure chamber 39, and closes the cut end together with the thermal expansion. By these actions, the annular ring 94 is pressed against the outer surface of the main body frame 5 and the annular seal groove 95, and the annular seal groove 95 and the annular ring
The lubricating oil is pushed in between the oil chamber A78 and the back pressure chamber 3 from the oil chamber A78a.
Prevent excessive leakage to 9.

Further, an annular ring made of resin having excellent flexibility.
94 expands its inner diameter along the outer surface of the annular seal groove 95 due to the pressure difference between the back pressure chamber 39 and the oil chamber A 78a, closes the cut end together with the thermal expansion, and Pressing against the outer surface further reduces direct leakage between the two spaces.

The oil groove 94 provided on the surface of the annular groove 94
The sliding surface between the annular ring 94 and the main body frame 5 is lubricated by the oil film of the lubricating oil that accumulates at a, thereby reducing the wear and sliding resistance of the sliding surface.

During the normal operation of the compressor, the orbiting scroll 18 is provided with a back pressure on the fixed scroll 15 side by the lubricating oil pressure of the high-pressure oil chamber A 78a and the lubricating oil pressure of the back pressure chamber 39, and the lap support disk 18c and the end plate The sliding surface 15b2 slides smoothly while maintaining an appropriate contact force, thereby minimizing the axial gap of the compression chamber.

The lubricating oil flowing into the back pressure chamber 39 intermittently passes through the outer peripheral space 37 through an oil hole 91 provided in the thrust bearing 20.
And the oil hole c3 provided in the lap support disk 18c
8c, small diameter injection holes 52a, 52b (see Fig. 14)
Through the first compression chambers 61a and 61b. The lubricating oil lubricates each sliding surface in the middle of the passage and seals the sliding gap.

The lubricating oil injected into the first compression chambers 61a and 61b merges with the lubricating oil flowing into the compression chamber (compression space) together with the suctioned refrigerant gas, and seals a minute gap between adjacent compression chambers with an oil film. The compressed refrigerant gas is discharged to the motor chamber 6 again through the discharge port 16 together with the compressed refrigerant gas while preventing the leakage of the compressed refrigerant gas and lubricating the sliding surfaces between the compression chambers.

The first reservoir 34 from the discharge chamber oil reservoir 34 passing through the back pressure chamber 39
In the oil supply path to the compression chambers 61a and 61b, the back pressure chamber 39 maintains a proper intermediate pressure between the discharge pressure and the suction pressure.

Further, since the compression ratio of the scroll refrigerant compressor is constant, when the differential pressure between the suction chamber 17 and the discharge chamber 2 is small, such as immediately after a cold start, or abnormal liquid compression occurs. In such a case, the orbiting scroll 18 separates from the fixed scroll 15 as described above, and is supported by the thrust bearing 20.

However, the thrust bearing 20 urged by the back pressure cannot support the abnormally increased compression chamber pressure load, and retreats in a direction to reduce the release gap 27, and is fixed to the lap support disk 18c of the orbiting scroll 18. The axial gap between the scroll 15 and the tip of the fixed scroll wrap 15a increases. This causes a lot of leakage between the compression chambers,
As indicated by the one-dot chain line 63a, the pressure in the compression chamber suddenly drops during compression.

Since the maximum distance of the orbiting scroll 18 from the fixed scroll 15 in the axial direction is restricted to about 70 μm, the pressure in the back pressure chamber 39 due to the direct communication between the outer peripheral space 37 and the suction chamber 17. After the change is suppressed and the compression load is instantaneously reduced, the thrust bearing 20 can instantly return to the original position, and the stable operation is continued again.

The orbiting scroll 18 is connected to the thrust bearing 20
When retreating toward the fixed scroll 15, the axial dimension between the tip of the orbiting scroll wrap 18a and the fixed scroll 15 also increases, but since the tip seal 98a is pressed against the fixed scroll 15 by the gas pressure on its back surface. Compressed refrigerant gas leakage from this portion hardly occurs.

On the other hand, the lap support disk of the orbiting scroll 18
The gap between 18c and the tip of the fixed scroll wrap 15b of the fixed scroll 15 is enlarged, and compressed refrigerant gas leaks in the compression chamber, causing the pressure in the compression chamber to drop rapidly.

Also, the orbiting scroll 18 and the fixed scroll
Also in the case where the foreign matter is caught in the axial gap between the thrust bearing 20 and the sliding member 15, the thrust bearing 20 retreats and removes the foreign matter, as described above.

The compression chamber pressure when instantaneous liquid compression occurs at the beginning of cold start or during steady-state operation is indicated by a dotted line 63 in FIG.
Abnormal over-compression occurs as described above, but the volume of the high-pressure space communicating with the discharge port 16 is large, and expansion is repeated while sequentially passing through the check valve chamber 50a, the discharge chamber 2, and the discharge chamber 2b, and the motor chamber The pressure change of 6 hardly occurs.

Further, as the operating speed of the compressor increases, the leakage of refrigerant gas in the compression chamber per unit time decreases. On the other hand, the opening time of the injection holes 52a and 52b per one turning motion is shortened, the amount of oil injection into the compression chamber per one turning motion is suppressed, and unnecessary oil compression is reduced. The passage resistance increases due to an increase in the number of shutoffs with the pressure chamber 39, the amount of lubricating oil flowing into the back pressure chamber 39 from the oil chamber A 78a is suppressed, and the pressure in the back pressure chamber 39 is appropriately maintained.

When the scroll refrigerant compressor incorporated in the heat pump refrigeration cycle and operating is switched from the heating operation to the defrosting operation, for a short time, the high pressure side becomes the evaporator and the low pressure side becomes the condenser side. Due to the connection, the pressure in the motor chamber 6 decreases instantaneously. Oil hole B following it
While the pressure of the back pressure chamber 39 and the pressure of the outer peripheral space 37 communicating with the motor chamber 6 via the oil reservoir 72 and the oil chamber A 78a sequentially decrease, the pressure of the suction chamber 17 and the compression chamber temporarily increases. When the back pressure rises and the proper back pressure cannot be maintained, the back pressure control valve device 25 provided on the lap support disk 18c as shown in FIG.
The plunger 29 moves toward the outer peripheral space 37 as shown in FIG. 13 against the back pressure of the lubricating oil flowing to the coil spring 53 and the back pressure chamber 39 by the lubricating oil pressure in the oil hole 54b communicating with the oil chamber B 78b. Then, the oil chamber B78b and the back pressure chamber 39 communicate with each other, high-pressure lubricating oil flows into the back pressure chamber 39, and the back pressure chamber 39 is returned to an appropriate pressure, and the plunger 29 is again oiled as shown in FIG. The oil chamber B78b is moved to the side of the chamber B78b, and the oil chamber B78b and the back pressure chamber 39 are shut off.

When the heat load on the evaporator side is high and the condensation capacity on the condenser side is high, the operation is performed with the suction pressure relatively high and the discharge pressure relatively low.

In such a case, since the pressure in the compression chamber becomes higher than that in the normal operation, it is necessary to make the pressure in the back pressure chamber higher than usual. The lubricating oil pressure in the oil hole 54b communicating with the oil chamber B 78b and the refrigerant pressure on the suction side communicating with the suction chamber 17 through the oil hole 54a resist the back pressure of the lubricating oil communicating with the coil spring 53 and the back pressure chamber 39. As shown in FIG. 13, the oil chamber B78b and the back pressure chamber 39 intermittently (or partially) communicate with each other to move toward the outer peripheral space 37, and high-pressure lubricating oil flows into the back pressure chamber 39. The pressure chamber 39 is maintained at an appropriate pressure.

Naturally, under the influence of the inertial force and the frictional force acting on the plunger 29, the plunger 29 moves between the small diameter portion cylinder 26b and the oil hole 54c to move toward the outer peripheral space 37. Since the communication area between them increases, the pressure in the back pressure chamber 39 increases as the operating speed of the compressor increases.

In the above embodiment, the compressed refrigerant gas during the final compression stroke was introduced into the release gap 27 provided on the back of the thrust bearing 20, but the compression chamber and the discharge port during the final compression stroke were introduced.
The discharged refrigerant gas in a region that communicates with 16 may be introduced into the release gap 27.

In the above-described embodiment, the sliding gap between the lap support disk 18c of the orbiting scroll 18 and the thrust bearing 20 is sealed only with the oil film of the lubricating oil.
Annular ring (82), as proposed in JP-159996
May be mounted on the back side of the lap support disk 18c to improve the sealing performance of the gap between the sliding portions between the back pressure chamber 39 and the outer peripheral space 37.

In FIG. 8, the number of sections per one turning motion in which the oil hole B38b and the back pressure chamber 39 are intermittently communicated is set to a large value. The opening position of the oil hole B38b is moved toward the center of the main body frame 5 so that the communication section per one turning motion between the oil hole B38b and the back pressure chamber 39 is reduced, so that the lubricating oil in the oil chamber A78a is reduced. It will be clear from the description of the prior art that the amount flowing into the back pressure chamber 39 and the compression chamber needs to be reduced. Accordingly, the pressure in the back pressure chamber 39 and the outer peripheral space 37 also decreases.

As described above, according to the above embodiment, the main bearing 12 and the orbiting scroll 18 which support the drive shaft 4 and are provided on the main body frame 5 and are close to the orbiting scroll 18.
The drive shaft 4 and the orbiting scroll 18
And a slewing bearing 18b that is slidably coupled between the bearing and the above-mentioned bearing (1.
2, 18b) and the back pressure chamber 39 provided outside the high pressure oil lubricating oil space (oil chamber A78a) on the anti-compression chamber side of the orbiting scroll 18 on the side of the high pressure lubricating oil space (oil chamber A78a). The annular ring 94 is defined between the main frame 5 and the orbiting scroll 18 and the annular ring 94 is mounted on the orbiting scroll 18 so that the center of the annular ring 94 and the center of the orbiting scroll 18 are substantially aligned. Since the high-pressure side back pressure chamber (oil chamber A 78 a) concentric with the orbiting scroll 18 orbits following the orbiting movement of the orbiting scroll 18, the high-pressure lubricating oil is always biased to the center of the orbiting scroll 18. In addition, the orbiting scroll 18 can be uniformly pressed toward the fixed scroll 15. Thereby, the orbiting scroll 18 can be suppressed from being inclined with respect to the fixed scroll 15, and the biased expansion of the compression chamber gap can be prevented, the leakage of compressed gas can be reduced, and the compression efficiency can be prevented from lowering.

The orbiting scroll 18 is a fixed scroll.
Since it does not incline with respect to 15, there is no one-side contact of the sliding surface of the slewing bearing 18b, and the bearing durability can be improved.

Also, the orbiting scroll 18 and the fixed scroll
No collision with 15 occurs, and damage to parts, generation of abnormal noise and vibration can be prevented.

In the above-described embodiment, the annular ring 94 is provided so as to protrude from the lap support disk 18c.
Annular seal groove 95 provided in the slewing bearing boss 18e
, The annular ring 94 can be provided without reducing the rigidity of the lap support disk 18c.

In the above embodiment, the main bearing 12 and the slewing bearing 18b are arranged adjacent to each other in the main shaft direction of the drive shaft 4. However, Japanese Patent Application Laid-Open No. 58-79684 and Japanese Patent Application Laid-Open No. 63-20549
As disclosed in Japanese Patent Application Publication No. 0-203, even in the case of the configuration in which the slewing bearing is disposed inside the main bearing, the same operation and effect as described above can be expected.

In the above-described embodiment, the structure and operation and effects of the vertical compressor are described. For example, the upstream side of the oil hole A (38a and others) in FIG.
The same operation and effect can be expected in the case of a configuration of a horizontal compressor having the bottom side of the compressor.

In the above embodiment, the outer peripheral space 37 is communicated with the first compression chambers 61a and 61b intermittently communicating with the suction chamber 17, but the outer peripheral space 37 may be communicated with the suction chamber 17. ,
In the case of this configuration, the pressure in the back pressure chamber 39 can be set to a pressure close to the suction chamber 17.

In the above embodiment, a refrigerant compressor has been described. However, similar effects can be expected in the case of other gas compressors such as oxygen, nitrogen, and helium using lubricating oil.

[0104]

As is apparent from the above embodiment, the first aspect of the present invention is as follows.
The present invention described in (1) provides a main frame that supports a drive shaft, a main bearing on a side close to the orbiting scroll, and a slewing bearing that is slidably coupled between the drive shaft and the orbiting scroll so as to impart a orbiting motion to the orbiting scroll. Parts are provided on the wrap support disk of the orbiting scroll, and the discharge chamber acts on the oil reservoir disposed in the closed case and communicates with the main bearing and the orbit bearing part. An annular ring that defines the outside and a back pressure chamber side provided on the anti-compression chamber side of the orbiting scroll is disposed between the main frame and the orbiting scroll, and the annular ring is mounted on the orbiting scroll, and the center of the annular ring And the center of the orbiting scroll almost coincides with each other. According to this configuration, the high-pressure side back pressure chamber concentric with the orbiting scroll orbits following the orbiting motion of the orbiting scroll. The high-pressure lubricating oil to the back urge posture, centered in Le, can be equally pressed orbiting scroll side of the fixed scroll. Thus, it is possible to suppress the orbiting scroll from inclining with respect to the fixed scroll, prevent the biased expansion of the compression chamber gap, reduce the leakage of the compressed gas, and prevent the compression efficiency from lowering.

Further, since the orbiting scroll does not incline with respect to the fixed scroll, there is no one-side contact of the sliding surface of the orbit bearing portion, and the durability of the bearing can be improved.

Further, the collision between the orbiting scroll and the fixed scroll does not occur, and it is possible to prevent damage to parts, generation of abnormal noise and vibration.

According to a second aspect of the present invention, the annular ring is disposed on the orbital bearing boss which constitutes the orbital bearing provided so as to protrude from the lap support disk. The annular ring can be provided without reducing the rigidity of the lap support disk.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a scroll refrigerant compressor showing one embodiment of the present invention.

FIG. 2 is an exploded view of main parts of the compressor.

FIG. 3 is a partial sectional view of a check valve device arranged at a discharge port of the compressor.

FIG. 4 is a perspective view of components of the check valve device in FIG. 3;

FIG. 5 is a perspective view of the same.

FIG. 6 is a perspective view of the same.

FIG. 7 is an exploded perspective view of small parts in the compressor.

FIG. 8 is a partial cross-sectional view of a main bearing in the compressor.

FIG. 9 is a perspective view of a seal component in the compressor.

FIG. 10 is a partial cross-sectional view of a thrust bearing portion of the compressor.

11 is a perspective view of the thrust bearing in FIG.

FIG. 12 is a sectional view for explaining the operation of the back pressure control valve device in the compressor.

FIG. 13 is a sectional view for explaining the operation.

FIG. 14 is a cross-sectional view taken along line AA in FIG. 1;

FIG. 15 is a characteristic diagram showing a change in pressure of refrigerant gas from a suction stroke to a discharge stroke of the compressor.

FIG. 16 is a longitudinal sectional view of a conventional scroll compressor.

FIG. 17 is a transverse sectional view taken along line 3-3 in FIG. 16;

[Explanation of symbols]

 Reference Signs List 4 drive shaft 5 main body frame 12 main bearing 15 fixed scroll 16 discharge port 17 suction chamber 18 turning scroll 18c lap support disk 15b end plate 18 turning bearing 20 thrust bearing 24 rotation preventing member 34 discharge chamber oil sump 41a spiral oil groove 41b spiral Oil groove 61a First compression chamber 78a Oil chamber A 78b Oil chamber B

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F04C 18/02 311 F04C 29/02 311

Claims (2)

(57) [Claims] An orbiting scroll wrap on a wrap supporting disk forming a part of a orbiting scroll is rotatable with respect to a spiral fixed scroll wrap formed on one surface of a head plate forming a part of a fixed scroll. A scroll-shaped compression space is formed between the two scrolls, a discharge port is provided at the center of the fixed scroll wrap, and a suction chamber is provided outside the fixed scroll wrap, and the compression space is provided from the suction side. Engaging the rotation-preventing member of the orbiting scroll between the main frame supporting the drive shaft and the orbiting scroll so as to compress the fluid by being partitioned into a plurality of compression chambers that continuously transition toward the discharge side. A scroll compression mechanism for orbiting the orbiting scroll is formed, the scroll compression mechanism is housed in a sealed case, and the orbiting scroll is attached to the main body frame. While providing the side main bearing near the Le,
A swivel bearing for slidingly connecting the drive shaft and the orbiting scroll is provided on the wrap support disk to apply orbiting motion to the orbiting scroll. An oil chamber that communicates with the main bearing and the orbiting bearing portion through an oil reservoir, and a back pressure chamber that is provided outside the oil chamber and on the side opposite to the compression chamber of the orbiting scroll. A scroll gas compressor having an annular ring to be disposed between the main body frame and the orbiting scroll, the annular ring being mounted on the orbiting scroll, and the center of the annular ring being substantially coincident with the center of the orbiting scroll. . 2. The scroll gas compressor according to claim 1, wherein the annular ring is disposed in an annular seal groove provided in a swivel bearing boss portion constituting a swivel bearing portion provided to protrude from the lap support disk.