JPH01301973A - scroll fluid machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a scroll compressor whose rotational speed is controlled over a wide rotational speed range from low speed to high speed, and particularly relates to a scroll compressor that supports the crankshaft in the above-mentioned scroll compressor. This invention relates to a lubricating device for a bearing.

[Conventional technology]

A scroll compressor meshes a fixed scroll member with an overwound wrap and an orbiting scroll with a similar spiral wrap, and rotates the orbiting scroll relative to the fixed scroll to compress and discharge fluid. It is equipped with a crankshaft to rotate the scroll. The support structure and oil supply method for supporting the crankshaft are described in Japanese Patent Application Laid-open No. 59-115488, in which a first sliding bearing is provided between the orbiting scroll, the crank part of the crankshaft, and the orbiting scroll. The crankshaft is supported by a second sliding bearing or rolling bearing and a third sliding bearing installed between the shaft portion of the crankshaft and the frame. Centrifugal force is applied to the lubricating oil through the provided eccentric oil supply path, and this is supplied to the third bearing.The centrifugal force generated by the rotation of the crankshaft, the discharge pressure, and the intermediate pressure (discharge The lubricating oil was supplied to the second bearing by the differential pressure between the pressure and the suction pressure.

In addition, as another method of supplying lubricating oil to bearings, there is
As described in Japanese Patent No. 8-126491, oil is supplied to the first and second bearings by the differential pressure between the discharge pressure and the intermediate pressure.
The third bearing was supplied with oil from a branch pipe using the centrifugal force of the crankshaft.

(Problems to be Solved by the Invention) In the prior art described above, a lubricating oil supply tray to each bearing is set on the premise that the scroll compressor is used at a constant rated rotational speed.

On the other hand, in recent years, it has become necessary to incorporate a scroll compressor into a refrigeration cycle and to operate the scroll compressor over a wide range from a low speed range to a high speed range in accordance with the load conditions of the refrigeration cycle. If the rotational speed of the scroll compressor mentioned above is controlled under such operating conditions, the centrifugal force for lubrication becomes small, especially in the low-speed operating range, making it impossible to secure a sufficient amount of lubrication, which can easily lead to damage to the bearings. It had the following drawback.

Moreover, since the oil supply using the differential pressure is performed from the middle of the second bearing, a discharge pressure is applied between the two second and third bearings.

Therefore, a spiral groove or a discharge hole for discharging the lubricating oil is required, which requires a lot of processing time.

A first object of the present invention is to provide an oil supply device that secures the amount of oil supply even in a low-speed operating range when controlling the rotation speed of a scroll compressor with an inverter, and prevents wear and seizure of bearings.

The second purpose is to provide an inexpensive oil supply device that requires a small number of processes.

The third purpose is to appropriately control the amount of oil supplied to each bearing.

[Means to solve the problem]

The first object is achieved by providing all the constituent bearings with a bearing structure in which oil is supplied using a differential pressure between the discharge pressure and the intermediate pressure.

The second object is achieved by installing a rolling bearing on the frame near the crank portion of the crankshaft, and installing a sliding bearing on the other end of the frame for performing the differential pressure oil supply.

The third objective is achieved by setting the flow resistance of the oil supply path so as to provide an oil supply flow rate that satisfies the most severe lubrication conditions within a set rotational speed, or by providing a mechanical oil drainage mechanism.

[Effect]

First, since all the bearings are designed to be lubricated by the differential pressure between the discharge pressure and the intermediate pressure, a substantially constant amount of lubricant can be supplied to the bearings regardless of the rotational speed of the compressor.

Secondly, a rolling bearing is installed on the frame near the crank side of the crankshaft, and a slide bearing is installed on the other end of the frame, so oil can be drained through the oil drain hole in the frame or through the sliding bearing. There is no need to process a spiral groove for use.

Thirdly, since the flow resistance of the oil supply path is set to provide an oil supply flow rate that satisfies the most severe lubrication conditions within the set rotational speed, bearing wear and seizure can be prevented in all operating ranges.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. FIG. 1 shows a cycle configuration diagram of a heat pump air conditioner driven by an inverter drive device 6. As shown in FIG.

This cycle includes a scroll compressor 1 and a heat exchanger 2 (installed indoors).

It is composed of a heat exchanger 3 (installed on the outdoor side), an expansion valve 4, a four-way valve 5, an inverter drive device 6, and a computer 7. During heating operation, high-pressure, high-temperature refrigerant gas discharged from the scroll compressor 1 is condensed and liquefied by the heat exchanger 2, then throttled by the expansion valve 4 to become low-pressure and low-temperature, and evaporated by the heat exchanger 3. Then, return to the suction side of the scroll compressor 1. During the cooling operation, the flow path is switched by the four-way valve 5, and the refrigerant gas flows in the opposite direction to that during the heating operation, is condensed in the heat exchanger 3, and evaporated in the heat exchanger 2.

A DC brushless motor is installed as the drive unit for the scroll compressor 1, and depending on the heating or cooling load conditions, the inverter drive unit 6 receives a speed command from the computer 7 to adjust the speed from about 30 Hz to 120 Hz.
Change the operating range to high speeds around Hz.

Figure 2 shows a vertically installed hermetic scroll compressor 1 of the present invention.
A cross-sectional view of the overall structure is shown.

In FIG. 2, a compressor section 9 is located above the airtight container 8, and an electric motor (for example, a DC brushless motor) 10 is located below.
are arranged respectively.

A lubricating oil reservoir 11 is formed at the bottom of the closed container 8. The compressor section 9 includes a fixed scroll 12 having a spiral wrap 12a on an end plate 12b, and a fixed scroll 12 having a spiral wrap 12a on an end plate 12b.
The frame 14 is integrally fastened to the fixed scroll 12 and supports the orbiting scroll 13, and the wraps of the fixed scroll 12 and the orbiting scroll 13 are engaged with each other. It has a vertical configuration.

Further, an Oldham mechanism 15 is provided between the orbiting scroll 13 and the frame 14 to prevent the orbiting scroll 13 from rotating. The electric motor 1° is press-fitted into the closed container 8 and is configured to rotate the orbiting scroll 13 via the crankshaft 16.

The shaft portion 16a of the crankshaft 16 is supported by a second bearing 17 and a third bearing 18 provided on the frame 14. Further, the crank portion 16b is fitted with a first bearing 19 provided on the back surface of the orbiting scroll 13. Note that these bearings may be indirectly supported by the frame.

Inside the crankshaft 16 are a second bearing 17 and a third bearing 18.
An oil supply passage 20 that guides lubricating oil to the first bearing 19 is provided along the axis of the shaft portion 16a of the crankshaft 16. Further, the lubricating oil in the oil reservoir 11 is extended to the shaft portion 16a and the shaft end of the electric motor 10 is sucked up to the oil supply passage 2.
0 is provided.

In the compressor section 9, the orbiting scroll 13 is connected to the electric motor 10.
The orbiting scroll 13. Fixed scroll 12
As the space (compression chamber) formed by the scroll moves toward the center of the scroll, its volume decreases to compress the sucked refrigerant gas. The compressed refrigerant gas is discharged from a discharge port 23 provided at the center of the end plate 12b of the fixed scroll to an upper space 24 within the closed container.

Furthermore, an intermediate pressure chamber 22 is formed on the back surface of the orbiting scroll to which gas during the compression stroke is guided. Intermediate pressure chamber 2
The pressure No. 2 is an intermediate pressure between the suction pressure and the discharge pressure of the refrigerant gas. FIG. 3 is an enlarged view for explaining the bearing configuration in more detail. The second bearing 17 has an outer ring 17a,
This is a roller bearing consisting of an inner ring 17, rollers 17c, etc., and a thrust bearing 25 is provided at the lower end of the inner ring 17b to support the crankshaft 16. A groove is provided on the surface of the thrust bearing 25.

The first bearing is lubricated at a discharge pressure Pa, an intermediate pressure P,
Which is done by differential pressure.

Furthermore, an axial groove 26 is provided on the surface of the crankshaft 16 that slides on the third bearing 18 . An oil supply hole 27 is provided at the lower end of the axial groove 26 that extends to the vicinity of the lower end of the third bearing 22 so as to communicate with the oil supply passage 20 .

Further, the upper end of the axial groove 26 communicates with a space formed between the frame 14 and the crankshaft 16 above the third bearing 18. Therefore, there is an intermediate pressure section 2 between the upper end surface of the third bearing 18, that is, between the second bearing and the third bearing.
0a is formed, the intermediate pressure portion 20a thereof has a pressure Pal slightly higher than the pressure of the intermediate pressure chamber 22, and the pressure at the lower end is in a discharge pressure P- state. The lubricating oil passes through the oil supply passage 20 from the oil supply amount [21], flows through the oil supply hole 27 and the axial groove 26 due to the differential pressure between the discharge pressure P- and the intermediate pressure P, and lubricates the third bearing 18. , the thrust bearing 25 is subjected to the intermediate pressure p, and the roller pressure F.
Due to the differential pressure of ax (P Ill> F ax), the second
After the bearing 17 is lubricated by the differential pressure between the pressure Pmx of the roller part and the pressure Pm (pat>p+m) of the intermediate pressure chamber, the other bearing 17 is lubricated to the intermediate pressure chamber 22, and the other bearing 19 is lubricated,
It flows into the intermediate pressure chamber 22. That is, the lubricating oil inlet of each bearing and the intermediate pressure chamber are all set to communicate with each other, and all the lubricating oil supplied to each bearing flows into the intermediate pressure chamber. The lubricating oil that has flowed into the intermediate pressure chamber 22 flows into the compression chamber through the intermediate hole 13b, and flows into the upper space 24 in the closed container 8 through the discharge port 23 provided at the center of the fixed scroll 12 in a state where it is mixed with refrigerant gas. Intermediate pressure chamber 22 as above 0 to discharge
The oil used to lubricate the first bearing 19 and the third bearing 18 flows into the first bearing 19 and the third bearing 18 . Further, the third bearing 18 is not provided with a groove for an oil reservoir.

When the load changes during heating and cooling operation.

A speed command from the computer 7 is transferred to the inverter drive device 6, and based on the speed command value, the electric motor 10 changes its rotational speed within a range of about 30 Hz to 120 Hz.

In the present invention, as described above, oil is supplied to the second bearing 17, the third bearing 18, the thrust bearing 25, and the first bearing 19 using the differential pressure between the discharge pressure and the intermediate pressure. Therefore, once the flow path resistance is determined, a substantially constant oil supply flow rate commensurate with the flow path resistance can be obtained regardless of the rotational speed of the scroll compressor 1.

The flow path resistance is determined so as to ensure oil film thickness under strict conditions in terms of lubrication properties within the set circuit speed range, and to ensure an oil flow that sufficiently reduces the rise in bearing temperature. In the above method, the first bearing 19, the third bearing 18 and the thrust bearing 2
Since the flow path resistance is set at 5, a sufficient amount of oil can be ensured even in the low-speed operating range, which has been a problem in the past, and this has the effect of preventing bearing wear and seizure. In addition, since the flow path resistance is set to ensure the amount of oil supply under the most severe conditions within the set rotational speed range, it is possible to prevent wear and seizure of the bearing in the entire operating range. Furthermore, since the bearing structure that supports the shaft portion 16a of the crankshaft 16 is supported by two bearings, the second bearing 17 and the third bearing 18, and the bearing is lubricated only by the differential pressure oil supply, the frame There is no need to machine an oil drainage hole in the third bearing or a spiral groove for oil drainage in the third bearing, and the number of bearings can be reduced, resulting in an inexpensive bearing structure.

Another embodiment of the present invention is shown in FIG. 4, and the purpose of this embodiment is to drain the lubricating oil that has flowed into the intermediate pressure chamber after lubricating each bearing without passing through the intermediate hole 13c. An annular groove 28 is provided at the bottom of the frame 14 to collect the lubricating oil that has flowed into the intermediate pressure chamber, and the frame 14 has a cylinder hole, and a piston 30 that reciprocates within the cylinder hole using the movement of a balance weight. ．． A groove 29 for sucking lubricating oil, a cylinder head 31, a discharge hole 32 provided in the cylinder head 31, a discharge valve 33, and a piston 3.
An oil drain pump consisting of a spring 34 for returning zero is provided. The rest of the structure is the same as the embodiment shown in FIG. As described above, the lubricating oil that lubricates each bearing due to the pressure difference between the discharge pressure and the intermediate pressure finally flows into the intermediate pressure chamber and accumulates in the annular groove 28 provided at the bottom thereof. The balance weight 36 rotates with the rotation of the crankshaft 16, and when the balance weight 36 comes to the pump side as shown in FIG. 8 and return it to the lubricating oil reservoir 11 at the bottom of the closed container 8.
As the balance weight 34 rotates to the opposite side, the piston 30 is pushed by the spring 34 and moves toward the balance weight, and the lubricating oil accumulated in the annular groove 28 is sucked into the cylinder 35 from the groove 29. By repeating this operation, the lubricating oil that has flowed into the intermediate pressure chamber is transferred to the intermediate hole 13b.
The oil is drained without passing through. In the present invention, the motion of the balance weight is used, but a rotary pump or a reciprocating pump may be constructed using the orbiting motion of the orbiting scroll. According to the embodiment of the present invention, in addition to the effects explained in the embodiments of FIGS. The weight 36 further prevents the oil from being stirred, which has the effect of reducing the compressor power.

Another embodiment of the present invention will be described with reference to FIGS. 5 and 6.

FIG. 5 is a vertical cross section showing the overall structure of a horizontal scroll compressor according to another embodiment of the present invention. In Figure 5,
A scroll compressor section 9 and an electric motor (for example, a DC brushless motor) 10 for driving the scroll compressor section 9 are horizontally arranged and housed in the closed container 8, and an oil reservoir 11 is formed below the container 8.

The scroll compressor section 9 is composed of an orbiting scroll 13, a fixed scroll 12, a drive shaft 16 that is driven by an electric motor 10 and has crank oil, a frame 14, and an anti-rotation mechanism 40.

The orbiting scroll 13 has a spiral wrap 13a on an end plate 13b. Further, a drive shaft 16 is provided on the back side of the mirror plate 13b.
A first bearing 19 into which the crank portion 16a is inserted is provided, and the end plate 13b is provided with a pressure guiding hole 13c that communicates the intermediate pressure chamber 22 with the space of the wrap 13a during compression.

The fixed scroll 12 fixed to the container 8 is also attached to the end plate 1.
2b has a spiral wrap 12a. Further, a suction hole 41 is provided at the outer circumference of the wrap, and a discharge hole 23 is provided at the center of the wrap.

A frame 14 fixed to the container 8 has a second bearing 17 supporting a drive shaft 16, a third bearing 47°, and a thrust bearing 2.
5 is installed, and the orbiting scroll 13 is connected to the fixed scroll 1.
An intermediate pressure chamber 22 for applying appropriate pressing force to the orbiting scroll 13 is provided.

FIG. 6 shows an enlarged view of the arrangement of the oil supply holes.

Due to the orbiting movement of the orbiting scroll 13, the center of the oil supply hole 43f performs an orbit movement with the same radius as the crank radius of the crank 16a, that is, the orbiting radius of the orbiting scroll. The length is set to be longer than the radius of the orbiting movement of the oil supply hole 43f, so that the oil supply holes 43f and 43d are always in communication during the orbiting movement of the orbiting scroll 13.

The second bearing 17 is a roller bearing consisting of an outer ring, an inner ring, rollers, etc., and a thrust bearing is provided at the end of the inner ring on the motor side to receive the thrust force applied to the crankshaft. A groove is provided on the surface of the thrust bearing 25. An axial groove 26 is provided on the surface of the crankshaft 16 that slides on the third bearing 18, similar to that shown in FIG. The frame 14 and the crankshaft 1 on the compressor side side of the third bearing 47 from the vicinity
6 and is provided in communication with the space formed between the two. or,
The crankshaft 16 has an axial groove provided in the crankshaft near the end on the motor side, which communicates with an oil supply hole 43a provided at the center of the crankshaft 16 and not open at the shaft end on the motor side. ing.

Next, the operation of the scroll compressor will be explained. When the drive shaft 16 is rotated by the electric motor 10, the crank 16
Due to the rotational movement of a and the action of the rotation prevention mechanism 40, the orbiting scroll 13 performs an orbiting movement without rotating on its own axis.

As a result, the orbiting scroll 13 and the fixed scroll 12 overlap 12a.

The space formed by 13a and end plates 12b and 13b reduces its volume while moving to the center, compresses the gas sucked in through suction hole 41, and discharges it through discharge hole 23. The discharged gas passes through a passage 45 formed in the end plate 12b of the fixed scroll 12 and the frame 14, cools the electric motor 10, and is then discharged from the discharge pipe 46. When the scroll performs a compression action, a force acts to separate the orbiting scroll 13 and the fixed scroll 12. To prevent this, the pressure in the intermediate pressure chamber 22 on the back of the orbiting scroll is controlled by the pressure guiding hole 13b. , is maintained at a pressure lower than the discharge pressure and higher than the suction pressure (intermediate pressure).

Therefore, the end of the third bearing 47 on the compression mechanism side, that is,
An intermediate pressure section 43g is formed between the second bearing and the third bearing, and the intermediate pressure section 43g is at a pressure Pal slightly higher than the pressure in the intermediate pressure chamber 22, and the end on the motor side is discharged. The pressure is P.

As a result, the end surfaces of the bearing 19 of the orbiting scroll and the second bearing 17 of the frame on the side of the intermediate pressure chamber 22 are maintained at the intermediate pressure, so that the oil in the oil reservoir 11 is supplied to the oil supply holes 43c and 43d provided in the fixed scroll. and the oil supply hole 43 of the drive shaft via the oil supply holes 43e and 43f provided in the orbiting scroll.
The oil is guided to the end of point a at the discharge pressure, the oil supply hole 43a is filled with oil, and the third bearing 47 is further supplied with oil via the oil supply hole 43b by the differential pressure between the discharge pressure and the intermediate pressure.

After lubricating the third bearing 26, the thrust bearing 25 is adjusted between the intermediate pressure P+ml and the roller pressure Pmx (P m i
> P @
> Pl) and flows into the intermediate pressure chamber 22 with lubrication due to the differential pressure. Further, the bearing 19 is supplied with oil sent to its end face through the oil supply hole 43f due to the differential pressure between the discharge pressure and the intermediate pressure, and the oil flows into the intermediate pressure chamber 22.

The lubricating oil that has flowed into the intermediate pressure chamber 22 flows into the compression chamber through the intermediate hole 13c, is mixed with refrigerant gas, and is discharged into the closed container 8 from the discharge port provided at the center of the fixed scroll 12, forming an oil sump. It will be collected on 11th.

The orbiting scroll 13 and the fixed scroll 12 are assembled with each other with the wraps 12b and 13b facing inward, and the orbiting scroll 13 is held between the fixed scroll 12 and the pedestal 42 of the frame 14.

A rotation prevention mechanism 40 for preventing rotation of the orbiting scroll is installed between the back surface of the orbiting scroll and the frame.

The drive shaft 16 has a crank portion 16a whose one end is supported by the bearing 19. Also, there is an oil supply hole 4 in the drive @16.
3a is provided on the rotation center of #16. One end of this oil supply hole 43a is open to the end face of the crank portion 16a, and the oil supply hole 43a is opened to the bearing 18 via the oil supply hole 43b.

The end plate 12b of the fixed scroll 12 has an oil supply hole 43c communicating with the oil reservoir 11, and the end plate 13b of the orbiting scroll 13 and the fixed scroll 1 communicate with the oil supply hole 43c.
Oil supply hole 43 that opens in the part where the end plate 12b of No. 2 slides.
d is provided.

Further, a bearing 19 is provided in the base plate 13a of the orbiting scroll 13.
An oil supply hole 43e is provided which communicates the end face of the mirror plate 13b with the outer periphery of the mirror plate 13b, and the outer end of the oil supply hole 43e is closed with a screw 44. The inner end of the oil supply hole 43e faces the oil supply hole 43a in the drive shaft 16. Further, the oil supply hole 43 is provided in the sliding portion of the end plate 13b with the end plate 12b of the fixed scroll 12.
An oil supply hole 43f that communicates between the oil supply hole 43d in the fixed scroll 12 and the oil supply hole 43d in the fixed scroll 12 is provided.

With the above configuration, even in an inverter-driven horizontal scroll compressor, the second bearing 17. Third bearing 47. All bearings in the thrust bearing 25 are lubricated by the differential pressure between the discharge pressure and the intermediate pressure.
Even when the operating speed of the compressor is low, a sufficient flow of oil can be supplied to each bearing, so bearing wear and seizure can be prevented.

In addition, as mentioned above, the oil flow rate to obtain the required oil film thickness and cooling amount may be determined under the most severe bearing conditions within the compressor speed range where the flow path resistance of each bearing is set. In this way, bearing wear and seizure can be prevented.

Second, since the bearing structure that supports the crankshaft 16 is supported by two bearings, the second bearing 17 and the third bearing 47, and is lubricated only by differential pressure lubricating, there are holes in the frame for draining oil or There is no need to machine a spiral groove for oil discharge in the third bearing, and the number of bearings can be reduced, resulting in an inexpensive bearing configuration.

Further, an oil draining mechanism as shown in FIG. 4 may be provided in the frame 14 of the intermediate pressure chamber so as to drain the oil toward the oil reservoir 11. This can reduce oil agitation loss due to the balance weight. can.

Thirdly, by using a horizontal scroll compressor, installation becomes easier due to the positional relationship between the compressor and the heat exchanger within the air conditioner, and the air conditioner becomes smaller.

〔Effect of the invention〕

According to the present invention, firstly, all the bearings are designed to be lubricated by the differential pressure between the discharge pressure and the intermediate pressure, so that a substantially constant amount of lubricant is supplied to the bearings regardless of the rotational speed of the compressor. Since the oil can be supplied, a sufficient amount of oil can be ensured even in low-speed operating ranges, which has the effect of preventing bearing wear and seizure.

Second, the bearing structure that supports the shaft portion 16a of the crankshaft 16 is supported by two bearings, the second bearing 17 and the third bearing 18,
Since the structure is such that the bearing is lubricated only by the differential pressure oil supply, there is no need to machine an oil drainage hole in the frame or a spiral groove for oil drainage in the third bearing, and the number of bearings can be reduced. This has the effect of providing an inexpensive bearing configuration.

Thirdly, the flow resistance of the oil supply path is set to ensure the amount of oil supplied under the most severe conditions within the set rotational speed range, which has the effect of preventing bearing wear and seizure in the entire operating range. .

Furthermore, by providing the oil drainage mechanism in the frame of the intermediate pressure chamber, it is possible to reduce the oil agitation loss due to the balance weight, and there is an effect that a highly efficient compressor can be obtained.

[Brief explanation of the drawing]

Figure 1 is a diagram showing a cycle configuration equipped with an inverter.
FIG. 2 is a longitudinal cross-sectional view showing the structure of a vertically placed hermetic scroll compressor according to an embodiment of the present invention, FIG. 3 is an enlarged cross-sectional view of the bearing portion of FIG. 2, and FIG. An enlarged cross-sectional view of a bearing portion of another embodiment, FIG. 5 is a longitudinal cross-sectional view showing the structure of a horizontal hermetic scroll compressor of another embodiment of the present invention,
FIG. 6 is an enlarged sectional view of the oil supply portion. 1... Scroll compressor, 2, 3... Heat exchanger, 4
... Expansion valve, 5... Four-way valve, 6... Inverter drive device, 7... Computer, 8... Airtight container, 9
...Compressor section, 10...Electric motor, 11...Oil sump, 12...Fixed scroll, 13...Orbiting scroll, 12a, 13a...Wrap, 13a, 13b...
・Mirror plate, 14...frame. 16... Crankshaft, 17... Second bearing, 18...
...Third bearing, 19...First bearing, 2o...Oil supply passage, 20a...Intermediate pressure section, 21...Oil supply device, 2
2...Intermediate pressure chamber, 25...Thrust bearing, 26...
- Axial groove, 27... Oil supply hole, 43a, 43b - Oil supply hole, 43c. 43 d, 43 e, 43 f - oil supply hole, 43
g-...Intermediate pressure section, 45...Passage, 47...Third bearing. Fig. 1 'l-'' ko) and -21ta VJ Z Fig. Z2''-ji anti-r L 3 Fig. VJ4 Fig. 36--Half-shaft V worker 4th 6 Fig. 73ku 43C, d3d-tilting force Holes 43e, 43f

Claims (6)

[Claims] 1. A fixed scroll, an orbiting scroll meshed with the orbiting scroll, a crankshaft engaged with the orbiting scroll, a plurality of bearings supporting the crankshaft, a variable speed motor driving the crankshaft, and discharging these. a sealed container housed in a sealed space where pressure acts; a lubricating oil supply means for supplying lubricating oil stored in the sealed container to the plurality of bearings; and a discharge pressure and a suction pressure on a back surface of the orbiting scroll. In a scroll fluid machine, the crankshaft is located in the intermediate pressure chamber and rotates with a first bearing provided at an engaging portion between the orbiting scroll and the crankshaft. Supported by a second bearing provided on a side closer to the scroll and a third bearing provided on a side closer to the motor, and communication between the second bearing and the third bearing is communicated with the intermediate pressure chamber. to form an intermediate pressure section, one end of the lubricating oil supply means communicates with the lubricating oil in the closed container,
a first oil supply passage whose other end opens into the intermediate pressure chamber; and a first oil supply passage that branches from the oil supply passage, communicates with the intermediate pressure section via the third bearing, and further communicates with the intermediate pressure section via the second bearing. A scroll fluid machine characterized by having a second oil supply passage communicating with the chamber. 2. A fixed scroll, an orbiting scroll meshed with the orbiting scroll, a crankshaft engaged with the orbiting scroll, a plurality of bearings supporting the crankshaft, a variable speed motor driving the crankshaft, and discharging these. a sealed container housed in a sealed space where pressure acts; a lubricating oil supply means for supplying lubricating oil stored in the sealed container to the plurality of bearings; and a discharge pressure and a suction pressure on a back surface of the orbiting scroll. a scroll fluid machine equipped with an intermediate pressure chamber that applies an intermediate pressure; The lubricating oil supply means is supported by a second bearing provided on the side closer to the orbiting scroll and at least one third bearing provided on the side closer to the motor, and one end of the lubricating oil supply means is provided in the closed container. a first oil supply passage that communicates with lubricating oil and whose other end opens into the intermediate pressure chamber; and a bearing end of the third bearing that branches from the oil supply passage and that branched oil supply passage is closer to the motor. a second oil supply passageway that is opened at the middle pressure chamber, has a cross-sectional area that allows the opening part and the intermediate pressure chamber to supply a required maximum oil supply flow rate within a set rotational speed range, and communicates with the second bearing via the second bearing; A scroll fluid machine characterized by having: 3. The scroll fluid machine according to claim 1, wherein the second bearing is a rolling bearing. 4. Claim 1: The frame forming the intermediate pressure chamber is provided with an oil feeding mechanism for feeding oil from the intermediate pressure chamber into the sealed container.
Scroll fluid machine described in. 5. 5. The scroll fluid machine according to claim 4, wherein the fixed scroll and the orbiting scroll are arranged in an upper part and the motor is arranged in a lower part. 6. The scroll fluid machine according to claim 1, wherein the crankshaft is arranged in a direction perpendicular to the direction of gravity.