JPH01177483A - Scroll gas compressor - Google Patents

Abstract

PURPOSE:To reduce a starting load and to improve compression efficiency, by a method wherein a back pressure chamber and the oil reservoir of a delivery chamber are intercommunicated through a throttle passage, and a check valve device is located in the middle of an oil injection passage through which the back pressure chamber and a compression space are intercommunicated. CONSTITUTION:A revolving scroll 18 is situated between a body frame 5 and a stationary scroll 15. A back pressure chamber 39 is formed on the counter- compression space side of the revolving scroll 18. The back pressure chamber 39 is communicated to an oil reservoir 34 of a delivery chamber through the fine gap of a main bearing 12. The back pressure chamber is communicated to second compression chambers 51a and 51b, having a pressure lower than that of the back pressure chamber 39, through an oil injection passage 55 formed in an end plate 15b of the stationary scroll 15. A check valve 58 is situated in the middle of the oil injection passage 55. This constitution enables reduction of a starting load and improvement of compression efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to oil injection for scroll gas compressors.

Conventional technology Scroll compressors have a suction chamber on the outer periphery, a discharge port in the center of the spiral, and compressed fluid flows in one direction, unlike in reciprocating compressors and rotary compressors. It is generally known that a discharge valve for compression is not required, the compression ratio is constant, the discharge pulsation is relatively small (and a large discharge space is not required).

However, especially when compressing gas, it is necessary to make the dimensional accuracy of the scroll part extremely high in order to reduce the leakage gap in the compression part. The problem was that the machine cost was high and performance varied widely.

Therefore, as a measure to solve this type of problem, it is expected that the dimensional accuracy of the spiral part will be optimized and the compressor performance will be stabilized by using a sealing effect using a lubricating oil film to prevent gas leakage during compression. Broadly speaking, as shown in FIG. 14, a configuration can be considered in which lubricating oil at the bottom of the discharge chamber is directly flowed into the compression chamber during compression.

The figure shows a structure in which a motor 703 is placed in the upper part of an airtight container 701, and a compression part is placed in the lower part, and a space 702 inside the airtight container is used as a discharge chamber. There is a configuration in which the air is directly introduced into a compression chamber 723 during compression via a pipe 722 (Japanese Patent Laid-Open No. 57-8386).

Further, the configuration shown in FIG. 15 is also considered, and the orbiting scroll 80
1 is provided with a through hole 818 having a throttling effect that communicates the sealed space 809 and the back pressure chamber 817.
1 is pressed against the fixed scroll 802, and the lubricating oil in the oil reservoir 899 at the bottom of the motor 816, which communicates with the discharge chamber 812, flows through the longitudinal groove 71 provided in the crankshaft 807.
9.720.721, there is a configuration in which the flow flows into the back pressure chamber 817 through the sliding part gap of each bearing that supports the crankshaft 807, and further flows into the closed space 809 through the conduction hole 818 (Japanese Patent Application Laid-Open No. 59-110884).

Problems to be Solved by the Invention However, if the lubricating oil in the oil outlet 710 at the bottom of the closed container internal space 702 is equal to the discharge pressure as shown in FIG.
In a configuration where differential pressure is used to flow into the compression chamber 723 during compression, when used in a closed circulation system such as a refrigerant compressor,
While the compressor is stopped, a large amount of refrigerant that returns to the compressor from the refrigeration cycle outside the compressor due to its own weight and differential pressure accumulates in a liquefied state on the underside of the motor 703 above the oil sump 710, causing refrigerant liquid and lubricating oil to evaporate. In some cases, the oil may flow into the compression chamber 723 through the oil suction pipe 722 and fill it. In this situation, the compression load is too high and restart operation is not possible.
Even if the motor 703 has a large starting torque and can be restarted, the compressor will be damaged.

In addition, because the compression chamber 723 and the oil reservoir 710 are configured to constantly communicate with each other, there is no need for a discharge valve for fluid compression in the scroll compression mechanism, and the compression ratio is constant, so it can be connected to a closed cycle piping system. For a while after the operating compressor is started when the compressor is cold, the pressure in the oil sump 710 in the closed container interior space 702 continues to be lower than that in the compression chamber 723, and the gas in the process of being compressed in the compression chamber 723 flows back into the oil sump 710. However, the lubricating oil in the oil sump 710 is diffused by the backflow gas and flows out into the external piping system of the compressor together with the discharged gas, becoming empty.As a result, the pressure in the closed container space 702 decreases shortly after the compressor is started. Even if the pressure rises and becomes higher than the pressure in the compression chamber 723,
compression chamber 72 until the lubricating oil is collected again in sump 710.
There is no effect of sealing the gap between the compression chambers due to the inflow of lubricating oil into
There is a problem in that the durability of the sliding part is reduced due to a significant decrease in compression efficiency, an abnormal increase in temperature, and an abnormal increase in pressure in the compression chamber.

In addition, in the configuration in which the sealed space 809 and the back pressure chamber 817 are directly communicated as shown in FIG. 15 above, the sealed space 809 and the back pressure The pressure in the discharge chamber 812 continues to be lower than that in the chamber 817, and during compression the gas flows through the communication hole 81 and back pressure chamber 817.
, bearing gap of crankshaft 807, longitudinal groove 719
．． The lubricating oil flows back into the oil sump via 720 and 721, and the lubricating oil in the oil sump is diffused in the same way as in the above case, and in some cases, the lubricating oil flows out of the compressor together with the discharged gas. Furthermore, the lubricating oil stored in the back pressure chamber 817 and the bearing portion of the crankshaft 807 flows out. This resulted in insufficient lubrication of the sliding parts at the initial stage of cold start-up, which was the main cause of reduced durability.

In addition, even if liquid compression occurs in the sealed space 809 and the compression load increases rapidly due to an abnormal pressure rise, lubricating oil will leak as described above, and immediately after the sealed space returns to the normal pressure state, the back pressure chamber 817 The pressure has increased abnormally, and the back pressure causes the orbiting scroll 801 to
02, which caused problems such as friction and wear on the sliding surface, resulting in input loss and decreased durability.

Therefore, the present invention provides a check valve device in the middle of the oil supply passage from the back pressure chamber to the compression chamber to prevent the backflow of compressed gas and improve the compression efficiency and durability of the scroll by effectively utilizing lubricating oil. The present invention provides a gas compressor.

Means for Solving the Problems In order to solve the above problems, the scroll gas compressor of the present invention provides an oil sump in a discharge chamber where the back pressure chamber of the orbiting scroll communicates with the discharge port, or an oil sump and a throttle passage that communicate with the discharge chamber. It also communicates with the compression space, which has a lower pressure than the back pressure chamber, through an oil injection passage provided through the end plate of the fixed scroll or the lap support disk of the orbiting scroll, and there is a back check in the middle of the injection passage. This configuration includes a valve device.

Operation According to the above configuration, the compressor is started when cold, the intake gas is discharged into the discharge chamber through the compression space, and the pressure in the discharge chamber is gradually increased.

On the other hand, while the pressure in the compression space where the oil injection passage opens is higher than the discharge chamber pressure, the oil injection passage is shut off by the operation of the check valve device, and the gas during compression is discharged through the back pressure chamber and the throttle passage. The lubricating oil does not flow back into the oil sump in the chamber (or the oil sump leading to the discharge chamber), and the lubricating oil in the back pressure chamber and the throttle passage is maintained and used to lubricate the sliding surfaces.

Thereafter, the lubricating oil in the oil sump is supplied to the back pressure chamber through the throttle passage as the pressure in the discharge chamber increases, and is supplied to the compression space through the oil injection passage as the pressure in the back pressure chamber increases, creating a minute gap between the compression chambers. The compressor is sealed with an oil film to prevent compressed gas from leaking, improving compression efficiency and improving the durability of the sliding parts during the initial startup stage.

Further, even if liquid compression occurs in the compression space where the oil injection passage opens and the pressure rises abnormally, the check valve device operates so that the gas during compression does not flow back into the back pressure chamber, and the pressure in the back pressure chamber does not rise. As a result, the orbiting scroll retreats toward the back pressure chamber due to the compression space pressure, expanding the gap in the compression space, lowering the compression chamber pressure, and reducing overload.

Embodiments Below, scroll compressors according to embodiments of the present invention will be described with reference to the drawings.

In Fig. 1, 1 is a sealed iron case, the entire inside of which is in a high-pressure atmosphere communicating with the discharge chamber 2, with a motor 3 in the upper part and a compression part in the lower part, which is fixed to the 3 m rotor of the motor 3. Main body frame 5 of the compression part that supports the drive shaft 4
The interior of the sealed case 1 is partitioned into a motor chamber 6 and a discharge chamber.

The main body frame 5 is made of an aluminum alloy with excellent heat conduction properties, with the main purpose of reducing weight and dissipating heat in the bearing section.A liner 8 made of iron with excellent weldability is fixed to the outer periphery by shrink fitting. The outer peripheral surface is inscribed in the sealed case 1 all around and is partially fixed by welding.

The outer peripheral portions of both ends of the stator 3b of the motor 3 are supported and fixed by a bearing frame 9 and a main body frame 5 which are internally fixed to the sealed case 1. The drive shaft 4 includes an upper bearing 10° provided on a bearing frame 9, a lower bearing 11 provided on the upper end of the main body frame 5, a main bearing 12 provided in the center of the main body frame 5, and a t end face of the main body frame 5. and motor 3
The drive shaft 4 is supported by a thrust ball bearing 13 provided between the rotor 3a and the lower end surface of the rotor 3a, and an eccentric bearing 14 eccentric from the main axis of the drive shaft 4 is provided at its lower end.

A fixed scroll 15 made of aluminum alloy is fixed to the lower end surface of the main body frame 5, and the fixed scroll 15 consists of a spiral fixed scroll wrap 151 and an end plate 15b.
A discharge port 16 that opens at the beginning of a 5 m winding is also opened to the discharge chamber 2, and a fixed scroll wrap of 15 m is provided.
A suction chamber 17 is provided on the outer periphery of the suction chamber 17 .

An aluminum alloy consisting of a spiral orbiting scroll wrap 18m that meshes with a fixed scroll wrap 15m to form a compression chamber, and a wrap support disk 18a that stands upright with a rotation shaft 18b supported by an eccentric bearing 14 of a drive shaft 4. The orbiting scroll 18 made of manufactured by Nippon Steel is disposed surrounded by the fixed scroll 15, the main body frame 5, and the drive shaft 4, and has a sleeve 1 made of high-strength steel material on the outer periphery of the orbiting shaft tab.
9 is fixed by shrink fit, and the surface of the lap support disk 18c is hardened.

A spacer 21 is provided between a thrust bearing 20 that is restrained by a parallel bin 19 fixed to the main body frame 5 and can only move in the axial direction, and the end plate 15b of the fixed scroll 15. The dimensions are set approximately 0.015 to 0.020 mm larger than the thickness of the lap support disk 18c in order to improve the sealability of the sliding surface by an oil film.

The eccentric bearing space 36 between the bottom of the eccentric bearing 14 of the drive shaft 4 and the end of the orbiting shaft 18b of the orbiting scroll 18 and the outer peripheral space 37 of the lap support disc 18a are defined by the orbiting shaft 18b and the lap support disc 18c. They are communicated by an oil/water A38a provided in the.

As shown in FIGS. 2 and 6, the thrust bearing 20 is formed through a central portion into a shape consisting of two parallel straight portions 22 and two arcuate curved portions 23 connected thereto.

The Oldham ring 24 for preventing rotation of the orbiting scroll is made of a light alloy or resin material suitable for sinter molding, injection molding, etc., and is provided on one side of a thin annular plate 24m with parallel surfaces as shown in Fig. 4. The outer contour of the annular plate 24m consists of two parallel straight parts 25 and two arcuate curved parts 26 connected thereto, with the straight parts 25 being thrust as shown in FIG. It is able to engage and slide on the straight portion 22 of the bearing 20 with a small gap, and the side surface 24o of the parallel key portion 24b is connected to the straight portion 22 of the bearing 20.
5, and engage with a pair of key grooves 71 provided in the lap support disk 18a of the orbiting scroll 18 with a small gap as shown in FIGS. It is set.

Note that the inner contour of the annular plate 24m has a shape similar to the outer contour. Further, a recessed portion 24d provided at the root of the parallel key portion 24b also serves as a passage for lubricating oil.

As shown in Fig. 1 and Fig. 3, there is a release gap z of approximately 0.1 mm between the main body frame 5 and the thrust bearing 20.
7 is provided, and an annular groove 28 is also provided in the main body frame 5 opposite to the release gap 27, and a rubber seal ring 70 surrounding the annular groove 28 is provided between the main body frame 5 and the thrust bearing 20. It is installed.

The upper part of the motor chamber 6 and the discharge chamber 2 communicate with each other via a bypass discharge pipe 29 that passes through the side wall of the sealed case 1 and is connected to the upper part of the motor chamber 6. The opening position of the bypass discharge pipe 29 to the motor chamber 6 is as follows.
A discharge pipe 31 facing the side surface of the upper coil end 30 of the stator 3b and connected to the upper open end of the bypass discharge pipe 29 and the upper surface of the sealed case 1 is connected to a pull-out hole 32 provided in the bearing frame 5 and the closed case 1. 1 and the bearing frame 9, and communicate with each other via a punched metal 33 having a large number of small holes.

A discharge chamber oil reservoir 34 provided in the lower part of the motor chamber 6 is communicated with the upper part of the motor chamber 6 by a cooling passage 35 provided by cutting a part of the outer periphery of the stator 3b of the motor 3. The discharge chamber oil sump 34 also communicates with the annular m28 via an oil water B58b provided in the main body frame 5, and also communicates with the back pressure chamber 39 of the orbiting scroll 18 in which the Oldham ring 24 is disposed. It communicates through the small gap between the moving parts,
Furthermore, it also communicates with the eccentric bearing space 36 via an oil groove A40g provided in the eccentric bearing 14.

Further, the oil water B58b provided in the main body frame 5 also communicates with the spiral oil groove 41 provided on the surface of the lower shaft portion 4a corresponding to the lower bearing 11 of the drive shaft 4,
The winding direction of 41 is set so that a screw pump action using the viscosity of the lubricating oil occurs when the drive shaft 4 rotates in the forward direction.
Its terminal end is formed halfway to the lower bearing 4a.

As shown in FIGS. 6 and 7, the fixed scroll 15 is provided with an arc-shaped suction passage 42 that communicates both ends of the suction chamber 17, and a circular suction hole 43 perpendicular to the arc-shaped suction passage 42 is formed on the side surface of the fixed scroll wrap 15m. The bottom of the suction hole 43 is flat and reaches the side surface of the suction passage 42 . As shown in FIG. 8, the center of the suction hole 43 is offset from the bottom surface 44 of the suction passage 42, and the opening dimension W45 to the suction passage 42 is set smaller than the diameter dimension of the suction hole 43. In addition, an accumulator 46 is provided in the suction hole 43.
A suction pipe 47 is connected to the bottom surface 44 of the suction hole 43.
A circular thin steel plate is provided between the suction pipe end face 48 and the inner diameter dimension of the suction pipe 47 and the suction hole depth L49 between the suction pipe end face 48 and the bottom face 44, and is larger than the opening dimension W45. A check valve 50 is arranged. Check valve 50
The surface is coated with Teflon or rubber, which has poor oil wettability and is highly elastic.

Further, the second compression chamber 51 and the outer peripheral space 37, which do not communicate with either the suction chamber 17 or the discharge chamber 2, are connected to a small diameter injection hole 52 which opens into the second compression chamber 51 and is provided in the end plate 15b.
, an injection passage 55 consisting of an injection groove 54 formed by an end plate 15b and a resin heat insulating cover 53, and a stepped oil chamber C3E3c that opens into the outer peripheral space 37, and is connected to a large diameter part of the oil/water 38c. In 56,
As shown in FIG. 9, a check valve 58 made of a thin steel plate having a notch 57 in a part of its outer periphery and a coil spring 59 are arranged, and the coil spring 59 is pressed by a heat insulating cover 53 to form a check valve. 58 is always energized. As shown in FIGS. 10 and 11, the opening position of the oil chamber C38c to the outer peripheral space 37 is such that the orbiting scroll 18 is close to the end of the volume reduction stroke of the third compression chamber 60 communicating with the discharge port 16. When moved (see Fig. 10), the outer peripheral space 37 and oil chamber C
38 (!) is in communication with each other, and at other times (see FIG. 11), it is provided at a position where it is blocked by the wrap support disc tea.

In FIG. 12, the horizontal axis indicates the rotation angle of the drive shaft 4,
The vertical axis shows the refrigerant pressure, and shows the pressure change state of the refrigerant gas during the suction, compression, and discharge processes.The solid line 62 shows the pressure change during normal pressure operation, and the dotted line 63 shows the pressure change during abnormal pressure rise operation. represents.

In FIG. 13, the horizontal axis indicates the rotation angle of the drive shaft 4,
The vertical axis indicates the refrigerant pressure, and the solid line 64 indicates the injection hole 52a of the second compression chamber 51m, 51b that does not communicate with either the discharge chamber 2 or the suction chamber 17.

52, shows the pressure change at the opening position of b, and the dotted line 65
is a first compression chamber 61a communicating with the suction chamber 17;

61b (see FIG. 6) shows the pressure change at a fixed point to 1--The dashed line 66 indicates the third compression chamber Boa communicating with the discharge chamber 2;
The two-dot chain line 67 shows the pressure change at a fixed point of 60b, and the two-dot chain line 67 indicates the first compression chamber 61m, 81b and the second compression chamber 51m, 51b.
The double dotted line 68 shows the pressure change in the back pressure chamber 39.

The operation of the scroll gas compressor configured as above will be explained.

1 to 13, the drive shaft 4 is driven by the motor 3.
When driven to rotate, the orbiting scroll 18 makes an orbiting motion, and the suction refrigerant gas containing lubricating oil from the refrigeration cycle connected to the compressor flows through the suction pipe 47, suction hole 43, and suction passage 4 connected to the akinimulator 46. ? After passing through the suction chamber 17
flows into the compression chamber etm, 61b formed between the orbiting scroll 18 and the fixed scroll 15, and is confined within the compression chamber, and the second compression chamber 5 is always a closed space.
1 m + 51 b s Third compression chamber 60a, Bob
It is sequentially transferred and compressed, and is discharged into the discharge chamber 2 through the discharge port 16 in the center. The discharged refrigerant gas containing lubricating oil returns to the motor chamber 6 inside the compressor via the bypass discharge pipe 29 piped to the outside of the compressor, and then is discharged from the discharge pipe 31 to the external refrigeration cycle. When flowing into the chamber 6, it collides with the side surface of the upper coil end 30 of the motor 3 and adheres to the surface of the motor winding, and after separating a part of the lubricating oil, When passing through the hole 32, the lubricating oil is effectively separated due to its inertial force, surface adhesion, etc. when changing the flow direction or passing through the small hole of the punched metal 33.

A part of the lubricating oil separated from the discharge gas lubricates the sliding surface of the upper bearing, and then passes through the cooling passage 35 along with the remaining lubricating oil, and is collected in the lower discharge chamber oil sump 34 while cooling the motor 3. be done.

The lubricating oil in the discharge chamber oil sump 34 is supplied to the thrust ball bearing 13 by the screw pump action of the spiral oil groove 41 provided on the surface of the lower shaft portion 4m of the drive shaft 4, and the lubricating oil is supplied to the thrust ball bearing 13 at the lower end of the lower shaft portion 4m. When the lubricating oil passes through the small bearing gap in the main bearing 12, the sealing action of the oil film blocks the discharged refrigerant gas atmosphere of the motor chamber 6 from the upstream space of the main bearing 12.

When the lubricating oil containing melted discharge from the discharge chamber oil sump 34 and refrigerant gas passes through the minute gap of the main bearing 12, it is reduced to an intermediate pressure between the discharge pressure and the suction pressure and flows into the back pressure chamber 39. After that, the oil groove A40m of the eccentric bearing 14, the eccentric bearing space 36
, an oil film C38o that flows into the outer peripheral space 37 via an oil film A38 that passes through the orbiting scroll 18, and further opens intermittently;
Injection groove 54, injection hole 52m.

It flows into the second compression chambers 51m and 51b via 52b, and lubricates the sliding surfaces in the middle of the passage.

In addition, the discharge chamber oil reservoir 34 is connected to the annular groove 28 and the release gap 2.
7, the thrust bearing 20 is urged by the back pressure and comes into contact with the end surface of the spacer 21.

Furthermore, the lap support disk 18c of the orbiting scroll 18 slides smoothly with a slight gap maintained between the thrust bearing 20 and the end plate 15b of the fixed scroll 15. 18c
The gap between the end face of the orbiting scroll wrap 18m and the end plate 15b is also kept small to reduce gas leakage between adjacent compression chambers.

Injection hole 52m of second compression chamber 51m, 51b
, 52b openings undergo a pressure change 64 as shown in FIG. 13, which is instantaneously higher than the back pressure chamber pressure 68 which changes following the pressure in the discharge chamber 2. However, since the average pressure is low, the lubricating oil from the back pressure chamber 39 is intermittently supplied to the second compression chambers 51m and 51b.
The compressed refrigerant gas in the second compression chambers 51m and 5Ib that flows into the second compression chambers 51m and 5Ib and which is instantaneously higher than the back pressure chamber pressure 68 during normal operation is attenuated by the small diameter injection holes 52g and 52b.
There is little instantaneous backflow to the injection groove 54, and the pressure within the injection groove 54 does not become higher than the back pressure chamber pressure 68.

The lubricating oil injected into the second compression chambers 51m and 51b joins with the lubricating oil that has flowed into the compression chambers together with the suction refrigerant gas, and the minute gaps between adjacent compression chambers are sealed with an oil film to prevent compressed gas leakage. The compressed gas is again discharged into the discharge chamber 2 while lubricating the sliding surfaces between the compression chambers.

In addition, the lubricating oil supplied to the back pressure chamber 39 at a differential pressure acts on the orbiting scroll 18 with an intermediate pressure biasing force together with the elastic force of the seal ring 70 to move the lap support disk 18o onto the end plate 1.
A pressure oil film is sealed on the sliding surface of the thrust bearing 20 and the suction chamber 17 to block communication between the outer peripheral space 37 and the suction chamber 17, and a gap between the sliding surface of the thrust bearing 20 and the lap support disk 18c is also lubricated and sealed.

In addition, for a while after the cold start of the compressor, the pressure in the discharge chamber 2 remains at the second level, as can be understood from FIGS.
The pressure of the refrigerant gas in the middle of compression is lower than that of the compression chambers 51a and 51b.

51b to the back pressure chamber 39 via the injection passage 55.
However, the backflow to the outer circumferential space 37 is prevented by the non-return action of the check valve 58, and as the pressure in the discharge chamber 2 increases, the lubricating oil in the discharge chamber 2 flows into the back pressure chamber 39 and the outer circumference. Differential pressure oil is supplied to the inner space 37.

Therefore, the back pressure urging force on the thrust bearing 20 at the initial stage of cold start is generated by the pressure in the compression chamber, and the thrust bearing 20 moves back slightly while resisting the thrust load that tends to separate the orbiting scroll 18 from the fixed scroll 15. The axial clearance between the orbiting scroll 18 and the fixed scroll 15 is enlarged.

This causes leakage in the compression space, lowers the compression chamber pressure, and eliminates the compression load at the initial stage of startup.

Thereafter, as the pressure in the discharge chamber 2 increases, the lubricating oil in the outer peripheral space 37 flows from the injection holes 52a and 52b to the second compression chamber 51a, against the biasing force of the coil spring 59.
51b Hinge Extraction.

In addition, when instantaneous liquid compression occurs due to oil injection or other causes during initial cold start or steady operation, the compression chamber pressure will be affected by an abnormal pressure rise and overcompression, as shown by dotted line 63 in Figure 12. However, since the discharge chamber 2 and the volume of the high-pressure space communicating therewith are large, the increase in the discharge chamber pressure is extremely small.

Furthermore, due to liquid compression, the pressure in the injection groove 54 communicating with the second compression chambers sta and stb also increases abnormally.
Due to the throttling effect of the small-diameter oil chamber C38a and the check action of the check valve 58, the outer peripheral space 37 and the injection groove 54 are cut off. As a result, the pressure in the back pressure chamber 39 does not change, and the back pressure urging force acting on the back surface of the thrust bearing 20 also does not change. Therefore, during liquid compression, the excessive thrust force acting on the orbiting scroll 18 causes the thrust bearing 20 to retreat as described above, the pressure in the compression chamber decreases, and normal operation continues thereafter.

In addition, as the thrust bearing 20 retreats during liquid compression, the pressure in the compression chamber drops midway as shown by the dashed line 63m in FIG.

After the compressor stops, the orbiting scroll 1
A reverse rotation torque is generated at 8, the orbiting scroll 18 rotates in the reverse direction, and the discharged refrigerant gas flows back to the suction side. Following this backflow of the discharged refrigerant gas, the check valve 50 moves from the position shown in FIG. 6 to the position shown in FIG. The airtight seal prevents the reverse flow of the discharged refrigerant gas, the reverse rotation of the orbiting scroll 18 is stopped, and the space between the suction passage 42 and the discharge board 16 maintains the discharge pressure.

Moreover, with the check valve 58 of the injection passage as a border,
Although the passage communicating with the compression chamber has a discharge pressure, the space between the outer peripheral space 37 and the back pressure chamber 39 maintains an intermediate pressure for a while, and due to the slight inflow of lubricating oil from the discharge chamber oil sump 34. When the compressor stops and gradually approaches the discharge pressure, the orbiting scroll 18 reverses and stops at a position where the third compression chambers Boa and Sob are enlarged, and the opening to the outer peripheral space 37 of the oil chamber C38c is formed by a lap support disk. 18c.

After the compressor is stopped, the check valve 58 blocks the injection passage 55 due to the biasing force of the coil spring 59, so no lubricant oil flows into the compression chamber from the outer peripheral space 37.

Further, in the above embodiment, the lubricating oil in the discharge chamber oil reservoir 34 is
Although oil is injected into the compression chambers 51a and 51b, oil may be injected into the first compression chambers 61 and 61b communicating with the suction chamber 17 depending on the compressor usage conditions.

Further, in the above embodiment, the discharge chamber oil sump 34 and the back pressure chamber 39 are communicated through a small gap in the main bearing 12, but they may be directly communicated through a throttle passage.

Further, in the above embodiment, the check valve 58 is connected to the fixed scroll 1.
Although it is provided on the end plate 15b of No. 5, it may be provided on the orbiting shaft tab of the orbiting scroll 18 or the lap support disk 18c.

Furthermore, in the above embodiment, the refrigerant compressor was explained, but
Similar effects can be expected with other gas compressors such as oxygen, nitrogen, and helium that use lubricating oil.

As described above, according to the above embodiment, the orbiting scroll 18
is arranged between the main body frame 5 supporting the drive shaft 4 and the fixed scroll 15, and forms a back pressure chamber 39 of the orbiting scroll on the anti-compression space side of the orbiting scroll 18, and the back pressure chamber 39 is connected to the discharge port 16. It communicates with the discharge chamber oil sump 34 through a small gap in the main bearing 12, and also communicates with the back pressure chamber 39.
The second compression chambers 51m and 51b, which have a lower pressure, communicate with each other via an oil injection passage 55 provided in the end plate 15b of the fixed scroll 15.
By providing the check valve 58 in the middle of the oil injection passage 55, the oil injection passage is closed by the operation of the check valve 5B while the pressure in the second compression chambers 51m and 51b, which the oil injector passage 55 opens, is higher than the discharge chamber pressure. This provides an oil supply configuration in which the gas during compression does not flow back through the back pressure chamber 39 or the small gap in the main bearing 12. Therefore, even when the compression ratio is constant and the suction pressure is relatively high, such as during startup, and the compression chamber pressure is much higher than during stable operation, the back pressure chamber pressure is low.
Since the back pressure urging force on the orbiting scroll 18 is small, the orbiting scroll 18 separates from the fixed scroll 15 in the axial direction, widening the gap between the compression chambers, lowering the compression chamber pressure, and reducing the starting load.

In addition, the back pressure chamber 39 and the main bearing 12 due to gas backflow during compression
sliding parts, other sliding parts, and even the discharge chamber oil sump 34.
Since there is no loss of lubricating oil, it can be used for lubrication at the initial stage of startup when the pressure in the discharge chamber 2 is low and the supply of oil from the discharge chamber oil reservoir 34 is insufficient.This reduces the load at startup and prevents seizure of the sliding parts. It can be prevented.

After the pressure in the discharge chamber 2 has increased, sufficient oil supply can reduce friction loss and improve compression efficiency by supplying oil to the compression chamber.

In addition, even if liquid compression occurs in the second compression chambers 51m and 51b and the pressure rises abnormally, there is no backflow of compressed gas and the pressure in the back pressure chamber 39 does not change, as in the case described above, so the orbiting scroll 1
8 is easily separated from the fixed scroll 15 in the axial direction, the response of the overload reduction operation is quick, and the durability of sliding parts such as the main bearing 12 and compression mechanism parts can be improved. Furthermore, since the back pressure acting on the orbiting scroll 1B does not change significantly, even when the compression chamber returns to normal pressure, there will be no sliding part wear or power loss due to excessive back pressure.

In addition, immediately after the compressor is stopped, the discharge chamber oil sump 34 and the back pressure chamber 39
Due to the differential pressure between the Since it is sealed, there is no inflow of lubricating oil or liquid refrigerant from the discharge chamber oil sump 34 into the second compression chambers 51a, 51b, allowing smooth operation upon restart.

Effects of the Invention According to the present invention, an orbiting scroll is disposed between a main body frame supporting a drive shaft and a fixed scroll,
A back pressure chamber of the orbiting scroll is formed on the side of the anti-compression space of the orbiting scroll, and the back pressure chamber communicates with the oil reservoir of the discharge chamber communicating with the discharge port or the oil reservoir communicating with the discharge chamber via a throttle passage, and The compression space, which has a lower pressure than the back pressure chamber, communicates with the oil injection passage provided on the end plate of the fixed scroll or the lap support disk of the orbiting scroll, and by providing a check valve device in the middle of the oil injection passage. While the pressure in the compression space where the oil injection passage opens is higher than the discharge chamber pressure, the oil injection passage is quickly cut off by the operation of the check valve device, and the gas during compression flows into the discharge chamber through the back pressure chamber and the throttle passage. Because of the oil supply structure that does not flow back into the oil sump (or the oil sump leading to the discharge chamber), the compressor is used in a closed piping system, and the compression ratio is constant and the suction pressure is relatively high as at startup, and the compression chamber pressure is Even when the pressure is much higher than during stable operation, the back pressure chamber pressure is low and the back pressure urging force on the orbiting scroll is small, so the orbiting scroll separates from the fixed scroll in the axial direction, widening the gap between the compression chambers and compressing. It can lower the chamber pressure and reduce the starting load.

In addition, oil accumulation in the back pressure chamber and discharge chamber due to gas backflow during compression (
Also, there is no loss of lubricating oil from the oil sump leading to the discharge chamber.
In the early stages of startup, when the pressure in the discharge chamber is low and the oil supply from the oil sump in the discharge chamber (or the oil sump leading to the discharge chamber) is insufficient, the oil supply passage around the throttle passage, back pressure chamber, and downstream of the back pressure chamber. Lubrication of the sliding parts can be provided, reducing the load at startup and preventing seizure of the sliding parts. By supplying sufficient oil from an early stage as the pressure in the discharge chamber increases, friction loss in the sliding parts can be reduced, and compression efficiency can be improved by sealing the compression chamber gap with an oil film by oil injection into the compression space.

In addition, even if the pressure in the compression space increases abnormally due to liquid compression, etc., there is no backflow of compressed gas and the pressure in the back pressure chamber does not change as described above, so the orbiting scroll is likely to separate from the fixed scroll in the axial direction, causing overload. The response of the reduction operation is good and the durability of the sliding part of the orbiting scroll drive system can be improved. In addition, since the back pressure acting on the orbiting scroll does not change significantly, even when the compression space returns to normal pressure, there will be no wear on the sliding surface between the fixed scroll and the orbiting scroll due to excessive back pressure, There will be no loss.

In addition, even after the compressor is stopped, there is no backflow of fluid from the compression space to the back pressure chamber, and the back pressure chamber maintains an intermediate pressure for a while. The lubricating oil in the oil reservoir flows into the back pressure chamber due to the differential pressure between the oil reservoir and the oil reservoir, which lubricates the sliding parts during restart, thereby increasing durability.

In addition, after the pressure inside the compressor is balanced, the lubricating oil film interposed in the throttle passage between the back pressure chamber and the oil reservoir in the discharge chamber causes
The throttle passage is blocked and lubricant oil is prevented from flowing into the compression space from the oil sump, achieving smooth restart operation.

Furthermore, by supplying oil to the compression space, overload can be quickly reduced from the initial stage of startup to during continued operation, improving durability and increasing compression efficiency.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view of a scroll refrigerant compressor in an embodiment of the present invention, Fig. 2 is an exploded view of the main components of the compressor, and Fig. 3 is a detailed portion of the seal portion of the thrust bearing in Fig. 1. 4 is an external view of the Oldham ring in the same compressor, FIG. 5 is an assembled external view of the Oldham mechanism related to FIG. Figure 7 is an explanatory diagram of the position of the check valve at the suction pipe connection part connected to Figure 9, and Figure 8 is B-B in Figure 7.
Figure 9 is a partial cross-sectional view drawn by a line, and Figure 9 is an external view of the check valve used in the oil injection passage of the same compressor. Figures 10 and 11 are
The figures are an explanatory diagram of the movement of the compression chamber near the discharge port of the same compressor, Figure 12 is a characteristic diagram showing the pressure change of refrigerant gas from the suction stroke to the discharge stroke of the compressor, and Figure 13 is a diagram of each compression chamber. Characteristic diagram showing the pressure change at a fixed point in
4 and 15 are longitudinal sectional views of different conventional scroll compressors, respectively. 2...Discharge chamber, 3...Motor, 4...
...Drive shaft, 5...Body frame, 12...
Main bearing, 15...Fixed scroll, 151...
... Fixed scroll wrap, tab ... End plate, 16 ... Discharge port, 17, ... Suction chamber, 18 ... Orbiting scroll, 18a ... Orbiting scroll wrap, 18c...Wrap support disk, 34...Discharge chamber oil sump, 39...Back pressure chamber, 52m, 52b...Injection hole , 54-... Injection groove, 55...
Oil injection passage, 58... Check valve, 5
9... Coil spring. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure 3 Mountain - Eye Shako 4 - Layer Otsukin Tuna I5 - 11-face fixed sgrol 15a----m 'R scale rug 16- Death Evoto/'l--・Inhalation chamber 18 mountain One side rotating scroll rug , 38cm-・5 nails 6C 42-IT and 8 to K SO-11 backstop 10a,, 60b --3rd production 6/α, Otsu 1
b - 1st craft mouse ≧ Me 5 Shimokami Takashi Fig. 7 Now with Fig. 8 lδb 16cm - Fixed scroll 2 Relap Fig. 10 16-1rj - Departing boat tk
---Orbiting scroll wrap lδ mountain

Claims (1)

[Claims] The orbiting scroll wrap on the wrap supporting disk, which is a part of the orbiting scroll, is engaged with the spiral fixed scroll wrap formed on one surface of the end plate, which is a part of the fixed scroll, so as to be able to swing and rotate. A spiral compression space is formed in between, a discharge port is provided in the center of the fixed scroll wrap, a suction chamber is provided on the outside of the fixed scroll wrap, and the compression space is directed from the suction side to the discharge side. A scroll compression mechanism that compresses fluid is formed by partitioning into a plurality of compression chambers that continuously move, and the orbiting scroll is disposed between a main body frame that supports a drive shaft and the fixed scroll, and the orbiting scroll is A back pressure chamber of the orbiting scroll is formed on the side of the anti-compression space, and the back pressure chamber communicates with an oil sump in a discharge chamber communicating with the discharge port or an oil sump communicating with the discharge chamber via a throttle passage. In addition, the compression space having a lower pressure than the back pressure chamber communicates with the oil injection passage provided in the head plate or the lap support disk, and the scroll gas is provided with a check valve device in the middle of the injection passage. compressor.