JPH08121366A - Scroll compressor - Google Patents

Abstract

PURPOSE: To provide high bearing reliability, excellent compression efficiency, and a low oil rise amount, in a scroll compressor of a structure wherein a revolving scroll member is supported at an intermediate pressure in a back chamber. CONSTITUTION: A back pressure chamber is divided into a first space 14a the central part of which has an approximate delivery pressure and a second space 14b the outer peripheral part of which has an intermediate pressure by a seal member. Lubricating oil 17 is guided in the first space and the second space is communicated with a compression space 7 in the middle of compression through a small hole 11. A discharge oil passage 18 opened to the first space is provided and the discharge oil passage 19 is communicated with a discharge oil pipe through which the lubricating oil 17 is guided to the inner bottom of a closed container 10. This constitution, since there is no pressure difference between the upper and lower ends of a bearing 12, prevents pressure reduction foaming of a dissolved solvent in the lubricating oil 17, provides high bearing reliability, and provides high compression efficiency and a low oil rise amount since the lubricating oil; 17 is not mixed with compression gas in the middle of compression.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scroll compressor, and more particularly to a scroll compressor suitable as a refrigerant compressor for refrigeration and air conditioning, and as an air or other gas compressor.

[0002]

2. Description of the Related Art As shown in FIG. 10, a basic structure of a general scroll compressor includes a fixed scroll member 1 in which a spiral wrap 1b which stands upright on an end plate 1a is formed in a closed container 10, and the end plate 2a. Upright spiral wrap 2b
The orbiting scroll members 2 formed with the above are meshed with each other with the wraps inside, the frame 3 is coupled to the fixed scroll member 1, and further, between the frame 3 and the orbiting scroll member 3, rotation prevention such as Oldham ring is prevented. Mechanism member 4
Is provided.

When the crankshaft 6 is rotated by the rotation of the electric motor 5, the orbiting scroll member 2 connected to the crankpin 6a makes an orbiting motion with respect to the fixed scroll member 1.

With this orbital movement, the compression space 7 formed by the fixed scroll member 1 and the orbiting scroll member 2 is moved to the center to reduce the volume and compress the gas. When the compression space 7 reaches near the centers of the scroll members 1 and 2, the compression space 7 communicates with the discharge port 1c, and the compressed gas is discharged into the space inside the closed container 10.

In the scroll compressor having the above structure and operation, the fixed scroll member 1 and the orbiting scroll member 2 are provided.
The force for separating the two acts on the scroll members 1 and 2 by the pressure of the compressed gas existing in the compression space 7. Therefore, if left as it is, the scroll members 1 and 2 are separated from each other, and normal compression operation cannot be performed.
Therefore, as disclosed in, for example, Japanese Patent Publication No. 62-37238, a gas pressure is applied to the back pressure chamber on the back side of the orbiting scroll member 2 to apply an axial pressing force to the orbiting scroll member 2. This prevents the scroll members 1 and 2 from coming off.

The back pressure chamber is pressured to the inside of the closed container 10 by the lubricating oil supplied to the seal bearing 9 through the oil supply passage formed in the frame 3 and the crankshaft 6 and each element of the fixed scroll member 1. Since the back pressure chamber is in a sealed state and communicates with the compression space 7 in the middle of compression by the small hole 11 provided in the orbiting scroll member 2, the back pressure chamber follows the change of the suction input pressure and the suction pressure. It is the middle pressure of the discharge pressure. Further, the lubricating oil supplied to the seal bearing 9 flows into the back pressure chamber. The lubricating oil that has flowed into the back pressure chamber is further mixed with the compressed gas in the compression space 7 through the small holes 11 provided in the orbiting scroll member 2 and discharged into the space inside the closed container 10, and inside the closed container 10. Although the discharge gas and the lubricating oil are separated, the lubricating oil that cannot be separated is sent to the use place together with the gas through the discharge pipe 16 as it is. This is called oil spilling, but especially when the size of the compressor is reduced, it is not possible to secure a sufficient oil separation space in the closed container 10, and therefore sufficient separation is not performed and the oil spill amount increases. Will end up.

[0007]

In the conventional compressor, the back pressure chamber is pressure-sealed by the lubricating oil supplied to the frame 3, the fixed scroll member 1 and the seal bearing 9. is there. The sealed bearing 9 has a discharge pressure on the space side in the closed container and a back pressure chamber pressure on the back pressure chamber side (a pressure intermediate between the suction pressure and the discharge pressure: hereinafter referred to as an intermediate pressure). Therefore, a pressure gradient from the discharge pressure to the intermediate pressure is generated in the height direction of the seal bearing 9. When part of the lubricating oil supplied to the seal bearing 9 flows into the back pressure chamber, the pressure gradient causes the refrigerant dissolved in the lubricating oil to depressurize and foam. When decompression foaming of the refrigerant occurs, the oil film formed on the seal bearing 9 may be broken, failing to perform the original function of the bearing, failing to bear the bearing load, and eventually causing seizure damage to the bearing. .

The lubricating oil that has flowed into the back pressure chamber has a small hole 11
The compressed gas existing in the compressed space 7 during the compression is mixed therewith, and is discharged into the space in the closed container 10 through the discharge port 1c. In this case, lubricating oil close to the discharge temperature is mixed with the gas in the middle of compression, and the temperature of the compressed gas rises.
That is, the compression work is additionally required by the amount of temperature increase, and the compression efficiency is reduced. Further, it becomes necessary to separate the lubricating oil mixed with the discharge gas in the closed container 10.

The present invention has been made in view of the above problems, and an object thereof is a scroll compressor having a structure for supporting an orbiting scroll member by an intermediate pressure of a back pressure chamber formed on the back surface of the orbiting scroll member. In order to provide a scroll compressor that has high reliability of the bearing, prevents a decrease in efficiency due to mixing of lubricating oil with the compressed gas during compression, and has a small amount of lubricating oil mixed with the discharged gas (oil rising amount). To do.

[0010]

A feature of the present invention is that a scroll compression mechanism is housed in an airtight container, and a discharge port is communicated with an inner space of the airtight container to maintain the airtight pressure in the airtight container. The back pressure chamber formed by the orbiting scroll member, the fixed scroll member, and the frame is provided on the side opposite to the wrap of the back pressure chamber, and the back pressure chamber is provided at the center by a seal member provided between the orbiting scroll member and the frame. And a first space having a pressure substantially equal to the discharge pressure,
The suction pressure is maintained at an intermediate pressure of the discharge pressure by the communication passage that is in the outer peripheral portion and communicates with the compression space during compression.
It is composed of the space.

Still another feature is that the crankshaft has an oil supply passage which opens into the first space and guides the lubricating oil accumulated in the bottom of the closed container to the first space, and The structure is such that the first space is provided with an oil drain hole for discharging the lubricating oil from this space to the space in the closed container. Also, a waste oil pipe communicating with the oil drain hole to quickly return the lubricating oil to the bottom of the closed container, or a gas in the closed container on the inner wall of the closed container in the direction of opening the drain hole and the space inside the closed container. The scroll compressor is provided with a partition plate that blocks the flow of the scroll compressor. With these, conventionally, the lubricating oil in the back pressure chamber was introduced into the compression space to mix the compressed gas, but according to the present invention, the lubricating oil is mixed with the compressed gas to the oil sump at the bottom of the closed container. It is possible to put it back.

[0012]

According to the present invention, since the pressure of the first space has a pressure substantially equal to the discharge pressure, there is no pressure gradient in the bearing, and the reduced pressure foaming of the refrigerant dissolved in the lubricating oil occurs. Therefore, the oil film of the bearing is not broken and high reliability can be obtained.

Further, the lubricating oil flowing into the first space is
Except for the amount of oil that leaks into the second space through a small amount of sealing member and lubricates the Oldham ring, the oil is discharged from the oil discharge hole to the space inside the closed container through the oil discharge passage. Therefore, the lubricating oil hardly mixes with the compressed gas in the compression space through the small holes provided in the orbiting scroll member, and the temperature of the compressed gas is prevented from rising by the lubricating oil, and thus the compression efficiency is prevented from decreasing. In addition, the lubricating oil does not mix with the compressed gas during compression, and the lubricating oil discharged by the oil drain pipe and the partition plate is not mixed with the discharged gas in the space inside the closed container. A lubricating oil re-separation mechanism is not required, and a low oil rise amount can be achieved.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is an overall structural view of a scroll compressor showing an embodiment of the present invention, and FIG. 2 is a partially enlarged view thereof. A fixed scroll member 1 formed by vertically arranging a spiral wrap 1b on an end plate 1a and an orbiting scroll member 2 similarly formed by erecting a spiral wrap 2b on an end plate 2a are engaged with each other to form a fixed scroll member 2. , Are connected to the frame 3 by several bolts 13. The frame 3 includes a back pressure chamber on the back side of the orbiting scroll member 2.

The stator 5a of the electric motor 5 is fixed inside the closed container 10, and the rotor 5b is connected to the crankshaft 6. A crank pin 6a is provided at the end of the crank shaft 6.
Is provided and is inserted into the boss portion 2c formed in the central portion of the orbiting scroll member 2.

The rotation preventing member 4 such as an Oldham ring has a known structure per se, and it will be briefly described that it comprises a ring portion and a key portion, and the key portion is the orbiting scroll member 2.
Are fitted in at least one mutually orthogonal key grooves 1d and 2d provided on the rear surface of the fixed scroll member 1 and the end surface of the fixed scroll member 1, respectively. Instead of the key groove 1d formed in the fixed scroll member 1, a key groove may be formed in the frame 3 as in the related art.

A seal member 15 is provided between the frame 3 and the end face of the orbiting scroll member boss portion 2c, and the back pressure chamber 14 is provided in the first space 14 inside the seal member.
a and the second space of the outer peripheral portion, and both spaces 1
4a and 14b are sealed. FIG. 2 is an enlarged view of this portion. A ring groove 3a is formed in the frame 3 to hold the seal member 15, and the lower end surface of the boss portion 2c of the orbiting scroll member 2 is machined sufficiently smoothly so that the upper end surface of the seal member 15 and the boss portion 2c can be formed. The lower end surface pressure-seals the first space 14a and the second space 14b in the back pressure chamber. Also, the first space is almost the discharge pressure,
Since the second space has an intermediate pressure, the seal member 15 receives a force corresponding to the pressure difference from the inside to the outside. That is, the outer peripheral surface of the seal member 15 and the outer peripheral surface of the ring groove 3a are also sealed. The seal member 15 is, for example, a seal ring made of a fluororesin or a polyimide resin, and may be any one that can provide a necessary sealing property under the internal condition of the compressor during operation. Also, although one seal member is shown as an example, a plurality of seal members may be used in order to enhance the sealing property.

When the rotor 5b of the electric motor 5 rotates, the crankshaft 6 connected to the rotor 5b also rotates, and the orbiting scroll member 2 inserted in the crankpin 6a makes an orbiting motion, so that the fixed scroll wrap 1b turns into the orbiting scroll wrap 2b. The compression space 7 formed in 1 moves to the center while reducing the volume, and compresses the refrigerant gas sucked from the suction pipe 8. The compressed refrigerant gas passes through the discharge port 1c provided in the central portion of the fixed scroll member 1 and the closed container 10
It is discharged into the inner space. The discharged compressed gas is guided to the lower space of the frame 3 through a gas passage (not shown) provided on the side surface of the fixed scroll member 1 and the frame 3, and cools the electric motor 5 and then passes through the discharge pipe 16. And sent to the point of use.

An oil supply passage 6b is provided in the crankshaft 6, and the lubricating oil 1 stored in the bottom of the closed container 10 is caused by the centrifugal pump action as the crankshaft 6 rotates.
Lead 7 to the top. The oil supply passage 6b is open to the first space 14a in the back pressure chamber via the orbiting bearing 2e and the main bearing 12. When the lubricating oil 17 having a discharge pressure flows into the first space 14a, the first space 14a becomes a discharge pressure or a pressure substantially equal to the discharge pressure. Therefore, there is almost no pressure gradient between the upper end surface and the lower end surface of the main bearing 12,
The refrigerant dissolved in the lubricating oil does not foam under reduced pressure, so that high bearing reliability can be obtained.

Lubricating oil 17 flowing into the first space 14a
A small amount leaks from the seal member 15 into the second space 14b, lubricates the rotation preventing member 4 such as the Oldham ring and other sliding parts, is discharged into the compression space 7 through the small hole 11, and the rest is left in the main bearing 12. It is discharged into the space in the closed container 10 by gravity through a gap (a bearing gap or a cut surface provided on the crankshaft 6).

On the other hand, the second space 14b in the back pressure chamber communicates with the compression space 7 through the small hole 11 provided in the end plate 2a of the orbiting scroll member 2, and the second space 14b discharges pressure and suction. It is maintained at an intermediate pressure in the middle of the pressure. By adjusting the position of the small hole 11 and appropriately selecting the pressure of the compression space 7 for communication, the second space 14b is formed.
It is possible to apply an appropriate pressing force to the rear surface of the orbiting scroll member 2 by adjusting the intermediate pressure of the above, and thus to the force to disengage the scroll members 1 and 2. Further, since the lubricating oil does not mix with the compressed gas, it is not necessary to separate the oil contained in the discharge gas, and it is possible to obtain a low oil rise amount.

FIG. 3 shows another embodiment of the present invention. The difference from FIG. 1 is that an oil drain passage 18 is provided which opens in the first space 14a in the back pressure chamber and communicates with the space in the closed container 10. The pressure head of the centrifugal pump that guides the lubricating oil 17 to the first space 14a is set higher than the minimum head required to reliably push up the lubricating oil 17 to the upper end of the crankshaft 6, so that the first space 14a The internal pressure becomes slightly higher than the discharge pressure, and the lubricating oil 1 flowing into the first space 14a
It is possible to reliably drain the oil 7 from the oil drain passage 18 to the space inside the closed container 10.

Since the lubricating oil 17 in the first space 14a can be surely drained, an excessively small amount of the lubricating oil 17 leaks into the second space, and the small amount provided on the orbiting scroll member 2. The high temperature lubricating oil 17 hardly mixes with the compressed gas that is being compressed through the hole 11 and raises the temperature of the compressed gas, so that the compression efficiency can be prevented from lowering.

Furthermore, since the lubricating oil is not mixed in the compressed gas, it is not necessary to separate the oil contained in the discharge gas, and it is possible to obtain a low oil rise amount.

4 and 5 show another embodiment of the present invention. In any of the embodiments shown in FIG. 3, the lubricating oil 17 drained from the oil drain passage 18 to the internal space of the closed container 10 does not mix with the flow of the discharge gas in the closed container 10. Is.

In FIG. 4, the oil drain pipe 19 has a structure in which one end of the oil drain pipe 19 is communicated with the oil drain passage 18 and the other end is opened to the bottom of the closed container 10. The oil drain pipe 19 is provided through a cut surface 5c provided on the electric motor 5. As a result, the lubricating oil 17 drained from the first space of the back pressure chamber through the drain passage 18 can be reliably returned to the bottom oil sump without being mixed with the discharge gas flow in the closed container 10. . Furthermore, in FIG.
A partition plate 20 for shutting off the flow of discharge gas between the opening end of the sealed container 10 in the inner space of the closed container 10 and the cut surface 5c of the electric motor 5.
Is an example in which the inner wall of the closed container 10 is equipped with. The partition plate 20
The cut surface 5c of the electric motor 5 forms an oil guide passage.

In any of the embodiments shown in FIGS. 4 and 5, it is possible to prevent the discharge oil from being mixed with the discharge gas without directly interfering with the flow of the discharge gas in the space inside the closed container 10. Therefore, it is possible to achieve a low oil rise amount.

FIG. 9 shows another embodiment of the present invention. In the conventional scroll compressor, the orbiting scroll 2 has its end plate 2
It is supported by being sandwiched between the orbiting scroll support portion 3a of the frame and the fixed scroll end plate outer peripheral portion 1e on the outer periphery of a. Also in such a structure, as shown in FIG. 10, for example, the lower end surface of the orbiting scroll boss portion 2c and the bottom surface 3b of the space forming the back pressure chamber of the frame 3 are used as sealing surfaces, and the back pressure chamber is formed by the sealing member 15. First space 14a and second
Can be divided into a space 14b. In FIG.
Although the sliding bearing is used as the main bearing, the back pressure chamber can be similarly divided into two by using the rolling bearing.

FIG. 9 shows an example in which the embodiment of the present invention shown in FIG. 1 is applied to a conventional screw compressor.
The same can be applied to the embodiment shown in FIG. 5 as well, and the same operational effect as described above can be obtained.

FIGS. 6 and 7 show an embodiment of the seal member 15 common to all the embodiments. In FIG. 6, a groove 15a is provided on the upper end surface of the seal member 15. A rotation preventing member 4 such as an Oldham ring in the second space 14b of the back pressure chamber,
And to the sliding parts of the end plates of the scroll members 1 and 2,
The required amount of lubricating oil 17 can be supplied through the groove 15a. The supply amount of the lubricating oil 17 can be controlled by adjusting the number, width and depth of the grooves 15a.
Also, through the upper end surface of the seal member 15, the first member in the back pressure chamber
If the amount of lubricating oil leaking from the space 14a to the second space 14b is sufficient, the groove 15a may be omitted.

FIG. 7 shows an embodiment in which the notch 15b is provided in the seal member 15. The first space inside the seal member 15 is substantially at the discharge pressure, and the second space outside the seal member 15 is at an intermediate pressure, which is between the discharge pressure and the suction pressure. Therefore, the seal member 15 receives the force due to the pressure difference from the inside to the outside, and is deformed as shown in FIG. Here, as shown in FIG. 7, the notch 15b is formed in the seal member 15.
By providing the pressure difference, it is possible to adjust the diameter of the seal member 15 in response to the deformation when the force due to the pressure difference is applied, without impairing the sealability, and thus, the seal of the outer peripheral surface of the seal member 15 can be achieved. The quality is improved.

[0032]

As described above, according to the present invention, in the structure in which the orbiting scroll member is supported by the intermediate pressure of the back pressure chamber, there is almost no discharge pressure at which the lubricating oil in the central portion of the back pressure chamber flows. The structure is divided into the first space and the second space at the intermediate pressure of the outer peripheral portion so that the lubricating oil does not flow into the second space. It is possible to obtain a scroll compressor in which the efficiency is prevented from being lowered due to mixing in the oil and the amount of lubricating oil (oil rising amount) mixed in the discharge gas is small.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a scroll compressor showing an embodiment of the present invention.

FIG. 2 is a partially enlarged view showing a seal portion according to an embodiment of the present invention.

FIG. 3 is a vertical cross-sectional view of a scroll compressor showing another embodiment of the present invention.

FIG. 4 is a vertical sectional view of a scroll compressor showing still another embodiment of the present invention.

FIG. 5 is a vertical sectional view of a scroll compressor showing another embodiment of the present invention.

FIG. 6 is a diagram showing a seal member according to an embodiment of the present invention.

FIG. 7 is a view showing a seal member according to another embodiment of the present invention.

FIG. 8 is a partial enlarged view showing a seal portion according to an embodiment of the present invention.

FIG. 9 is a vertical sectional view of a scroll compressor showing still another embodiment of the present invention.

FIG. 10 is a vertical sectional view of a conventional scroll compressor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fixed scroll member 1a ... End plate 1b ... Fixed scroll wrap 1c ... Discharge port 1d ... Key groove 2 ... Orbiting scroll member 2a ... End plate 2b ... Orbiting scroll wrap 2c ... Boss part 2d ... Key groove 2e ... Orbiting bearing 3 ... Frame 4 ... Rotation preventing member 5 ... Electric motor 5a ... Stator 5b ... Rotor 6 ... Crank shaft 6a ... Crank pin 6b ... Oil supply passage 7 ... Compression space 8 ... Suction pipe 9 ... Seal bearing 10 ... Sealed container 11 ... Small hole 12 ... Main bearing 13 ... Bolt 14 ... Back pressure chamber 14a ... First space 14b ... Second space 15 ... Seal member 15a ... Groove 15b ... Notch 16 ... Discharge pipe 17 ... Lubricating oil 18 ... Oil discharge path 19 ... Oil discharge pipe 20 ... Partition Board

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location F04C 29/02 361 A (72) Inventor Hideyuki Ueda 390 Muramatsu, Shimizu, Shizuoka Prefecture Hitachi Air Conditioning Co., Ltd. System Division

Claims (6)

[Claims] 1. An orbiting scroll member and a fixed scroll member, which are composed of an end plate and a spiral wrap standing upright on the end plate, are meshed with each other with the wraps inside, and the frame is fixed scroll member so as to surround the orbiting scroll. The scroll compression mechanism that moves the compression space formed by both scroll members around the center to move the scroll members relative to each other so as to reduce the volume is housed in the closed container, and the inside of the closed container is discharged. A scroll compressor having a back pressure chamber formed by an orbiting scroll member, a fixed scroll member, and a frame on the opposite lap side of the orbiting scroll member while maintaining the pressure in the closed container at a discharge pressure by communicating with the outlet. , The back pressure is provided by at least one seal member provided between the orbiting scroll member and the frame. Has a first space in the central portion having a pressure substantially equal to the discharge pressure, and at least one communication passage communicating with the compression space formed in the outer peripheral portion by the scroll members being compressed. A scroll compressor comprising a second space maintained at a pressure intermediate between suction pressure and discharge pressure. 2. A main shaft has an oil supply passage that opens into the first space and guides the lubricating oil accumulated in the bottom of the closed container to the first space, and is sealed from the first space. The scroll compressor according to claim 1, wherein an oil drain hole for discharging the lubricating oil to the space inside the container is provided in the first space. 3. The scroll compressor according to claim 2, wherein the oil discharge hole is provided with an oil discharge pipe which communicates with the oil discharge hole and quickly returns the lubricating oil to the bottom of the closed container. 4. A guide passage for guiding the lubricating oil to the bottom of the hermetic container by providing a partition plate on the inner wall of the hermetic container in the direction of opening of the oil drain hole into the space of the hermetic container, the partition plate blocking the flow of gas in the hermetic container. The scroll compressor according to claim 2, wherein the scroll compressor is formed. 5. The second space in the outer peripheral portion of the back pressure chamber,
The scroll compressor according to claim 1, further comprising an Oldham ring which is a rotation preventing member. 6. The scroll compressor according to claim 1, wherein the seal member is provided with at least one cutout portion.