JP2766659B2 - Scroll fluid machine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a scroll compressor whose rotation speed is controlled over a wide rotation speed range from low speed to high speed, and particularly to a crankshaft in the scroll compressor described above. The present invention relates to a lubricating device for supporting a bearing unit.

[Conventional technology]

The scroll compressor meshes a fixed scroll member having an overwrapped wrap with a orbiting scroll having a similar spiral wrap, and turns the orbiting scroll with respect to the fixed scroll to compress and discharge fluid. It has a crankshaft for turning the scroll.
As described in JP-A-59-115488, a supporting structure for supporting the crankshaft and a first sliding bearing provided between the orbiting scroll and the crank portion of the crankshaft and the orbiting scroll are disclosed in JP-A-59-115488. The bearing is supported by a second sliding bearing or a rolling bearing and a third sliding bearing provided between the shaft portion of the crankshaft and the frame, and a method of lubricating these bearings is as follows. A centrifugal force is applied to the lubricating oil by an eccentric oil supply passage provided therein, and the centrifugal force is supplied to the third bearing. The lubricating oil is supplied to the second bearing by a differential pressure between the acting intermediate pressure (intermediate pressure between the discharge pressure and the suction pressure).

Another method of supplying lubricating oil to bearings is disclosed in
As described in JP-A-58-126491, lubrication to the first and second bearings is branched by the differential pressure between the discharge pressure and the intermediate pressure, and lubrication to the third bearing is branched by the centrifugal force of the crankshaft. It was done from a tube.

[Problems to be solved by the invention]

In the above-described related art, the supply amount of the lubricating oil to each bearing is set on the assumption that the scroll compressor is used at a constant rated rotation speed. On the other hand, in recent years, it has been required 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 according to the load conditions of the refrigeration cycle. When the rotation speed of the scroll compressor described above is controlled under such operating conditions, the centrifugal force for refueling becomes small, especially in a low speed operation range, so that a sufficient refueling amount cannot be secured and the bearing is likely to be damaged. Had the disadvantage that

Further, since the oil supply by the differential pressure is performed in the middle of the second bearing, a discharge pressure is generated between the two second and third bearings.

Therefore, a helical groove or a discharge hole for discharging the lubricating oil is required, which requires processing time and labor.

A first object of the present invention is to provide a lubricating device that secures a lubricating amount even in a low-speed operation range and prevents abrasion and seizure of a bearing when a rotational speed of a scroll compressor is controlled by an inverter.

A second object is to provide an inexpensive lubricating device with a small number of processes.

A third object is to appropriately control the amount of oil supplied to each bearing.

[Means for solving the problem]

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

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

The third object is achieved by setting the flow path resistance of the oil supply path so as to provide an oil supply flow rate that satisfies the strictest lubrication conditions within the set rotation speed, or by providing a mechanical oil discharge mechanism.

[Action]

Firstly, since all the bearings have a bearing structure in which oil is supplied by the differential pressure between the discharge pressure and the intermediate pressure, a substantially constant amount of oil can be supplied to the bearings regardless of the rotational speed of the compressor.

Secondly, since the rolling bearing is provided on the frame located near the crank side of the crankshaft and the sliding bearing is provided on the other end of the frame, the oil discharging hole is provided in the frame or the sliding bearing is provided with the oil discharging. There is no need to process the spiral groove.

Third, since the flow path resistance of the oil supply path is set so as to provide an oil supply flow rate that satisfies the strictest lubrication conditions within the set rotation speed, wear of the bearing,
Seizure can be prevented.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a cycle configuration diagram of a heat pump air conditioner driven by an inverter driving device 6. This cycle consists of scroll compressor 1, heat exchange 2
(Installed on the indoor side), heat exchanger 3 (installed on the outdoor side), expansion valve 4, four-way valve 5, inverter drive device 6,
It comprises a computer 7. During the heating operation, the high-pressure and high-temperature refrigerant gas discharged from the scroll compressor 1 is condensed and liquefied by the heat exchanger 2 and then condensed by the expansion valve 4 to become low-pressure and low-temperature. 3 to return to the suction side of the scroll compressor 1. In 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 in the heating operation, and is condensed in the heat exchanger 3,
It is evaporated in the heat exchanger 2.

A DC brushless motor is mounted as a driving device of the scroll compressor 1, and operates from a low speed of about 30Hz to a high speed of about 120Hz by an inverter driving device 6 according to a speed command from a computer 7 according to a load condition of heating or cooling. Change the range.

FIG. 2 is a sectional view showing the overall structure of a vertically mounted hermetic scroll compressor 1 according to the present invention.

In FIG. 2, a compressor unit 9 is provided above the closed container 8.
However, electric motors (for example, DC brushless motors) 10 are provided below.

A lubricating oil reservoir 11 is formed at the bottom of the closed container 8. The compressor unit 9 includes a spiral wrap 1 on a head plate 12b.
A fixed scroll 12 having a fixed scroll 12 having a spiral wrap 13a on a mirror plate 13b; and a frame 14 integrally fastened to the fixed scroll 12 and supporting the orbiting scroll 13. The wraps of the orbiting scroll 13 and the orbiting scroll 13 are engaged with each other.

An Oldham mechanism 15 for preventing the orbiting scroll 13 from rotating is provided between the orbiting scroll 13 and the frame 14. The electric motor 10 is press-fitted and fastened to the closed container 8,
The orbiting scroll 13 is caused to orbit 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. The crank portion 16b is fitted with a first bearing 19 provided on the back of the orbiting scroll 13. These bearings may be indirectly supported by the frame.

An oil supply passage 20 for guiding lubricating oil to a second bearing 17, a third bearing 18, and a first bearing 19 is provided in the crankshaft 16.
It is provided along the axis of the 16 shaft portions 16a. Shaft 1
An oil supply device 21 extending to 6a and sucking lubricating oil in an oil sump 11 at the shaft end of the electric motor 10 and feeding the lubricating oil into the oil supply passage 20.
Is provided.

When the orbiting scroll 13 is made to orbit via the crankshaft 16 driven by the electric motor 10, the compressor section 9 moves the space (compression chamber) formed by the orbiting scroll 13 and the fixed scroll 12 in the scroll center direction. The compressed refrigerant gas is compressed by reducing the volume as it moves to.
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 in the closed container.

An intermediate pressure chamber 22 is formed on the back of the orbiting scroll to guide the gas during the compression stroke. Intermediate pressure chamber 22
Is intermediate 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 is an outer ring 17a, an inner ring 1
7, a roller bearing composed of a roller 17c and the like. A thrust bearing 25 for supporting the crankshaft 16 is provided at a lower end of the inner ring 17b. A groove is provided on the surface of the thrust bearing 25, and an oil passage is formed between the thrust bearing and a frame supporting the bearing.

Lubrication of the first bearing is carried out Te cowpea the differential pressure between the discharge pressure P _d and the intermediate pressure P _m.

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

The upper end of the axial groove 26 communicates with a space formed between the frame 14 above the third bearing 18 and the crankshaft 16. Therefore, the upper end surface of the third bearing 18, that is,
An intermediate pressure portion 20a is formed between the second bearing and the third bearing. The intermediate pressure portion 20a has a pressure _Pm1 slightly higher than the pressure of the intermediate pressure chamber 22 and has a lower end portion. The pressure is in the discharge pressure _Pd state. Lubricating oil lubricates the line summer of the third bearing 18 flows by connexion the oil supply hole 27 and the axial grooves 26 in the differential pressure between the street discharge pressure P _d and the intermediate pressure P _m the oil supply passage 20 from the oil supply device 21 After that, the thrust bearing 25 is subjected to a pressure difference between the intermediate pressure P _m and the pressure P _m2 (P _m1 > P _m2 ) of the roller portion by the second bearing 1.
7 the pressure of the pressure P _{m @ 2} and the intermediate pressure chamber of the roller portion P _m (P _m2>
After lubrication is performed by the differential pressure of P _m ), the lubricating fluid flows into the intermediate pressure chamber 22 after lubricating the swivel bearing 19, and then flows into the intermediate pressure chamber 22. That is, the lubricating oil inflow portion 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 via the intermediate hole 13c, and is mixed with the refrigerant gas from the discharge port 23 provided at the center of the fixed scroll 12 to the upper space 24 in the closed vessel 8 in a mixed state. Discharge. As described above, the oil that has supplied the first bearing 19 and the third bearing 18 flows into the intermediate pressure chamber 22. The third bearing 18 is not provided with a groove for oil sump or the like.

When the load changes during the heating and cooling operations, the speed command of the computer 7 is transferred to the inverter driving device 6, and based on the speed command value, the electric motor 10 changes its rotation speed in a range of about 30 Hz to 120 Hz. It is like that.

In the present invention, as described above, oil supply to the second bearing 17, the third bearing 18, the thrust bearing 25, and the first bearing 19 is all performed using the differential pressure between the discharge pressure and the intermediate pressure. Therefore, when the flow path resistance is determined, a substantially constant oil supply flow rate corresponding thereto is obtained regardless of the rotation speed of the scroll compressor 1. The flow path resistance is determined such that the oil film thickness is ensured under the strictest conditions in terms of lubrication characteristics within the set circuit speed range, and the oil flow rate at which the rise in bearing temperature is sufficiently low flows. Since the flow resistances of the first bearing 19, the third bearing 18, and the thrust bearing 25 are set by the above-described method, a sufficient amount of lubrication can be ensured even in a low-speed operation range, which has been a problem in the past. Has the effect of preventing abrasion and seizure. In addition, since the flow path resistance is set so that the amount of lubrication can be secured under the strictest conditions in the set rotation speed range, there is an effect that wear and seizure of the bearing can be prevented in the entire operation range. Furthermore, the bearing structure for supporting the shaft portion 16a of the
And the third bearing 18 is used to lubricate the bearing only with the differential pressure lubrication.
There is no need to machine a hole for oil discharge in the frame or a helical groove for oil discharge in the third bearing, and the number of bearings can be reduced.

FIG. 4 shows another embodiment of the present invention. This example is
An object is to discharge the lubricating oil flowing into the intermediate pressure chamber after lubricating each bearing without passing through the intermediate hole 13c. Frame 1
An annular groove 28 for storing the lubricating oil flowing into the intermediate pressure chamber is provided at the bottom of 4, a cylinder hole in the frame 14, a piston 30 that reciprocates in the cylinder hole by using a balance weight and movement, Groove for inhaling lubricating oil 2
9, a cylinder head 31, a discharge hole 32 provided in the cylinder head 31, a discharge valve 33, and a spring for returning the piston 30.
An oil drain pump consisting of 34 is provided. Other configurations are the same as those of the embodiment shown in FIG. As described above, the lubricating oil that has lubricated each bearing by the differential pressure 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. 4, the piston 30 is moved to the cylinder head 31 to remove the lubricating oil in the cylinder into a closed container. 8 and is returned to the lubricating oil sump 11 at the bottom of the sealed container 8. As the balance weight 34 rotates and comes to the opposite side, the piston 30 is pushed by the spring 34 and moves to the balance weight side, and the lubricating oil accumulated in the annular groove 28 from the groove 29 is sucked into the cylinder 35. You. By repeating this operation, the lubricating oil that has flowed into the intermediate pressure chamber is
Oil is drained without passing through b. In the present invention, the movement of the balance weight is used, but a rotary pump or a reciprocating pump using the orbiting motion of the orbiting scroll may be configured. According to the embodiment of the present invention, in addition to the effects described in the embodiment of FIGS. The oil is further prevented from being agitated by the weight 36, and the power of the compressor is reduced.

Another embodiment of the present invention will be described with reference to FIGS. FIG. 5 is a longitudinal section showing the overall structure of a horizontal scroll compressor according to another embodiment of the present invention. In FIG. 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 a closed container 8, and an oil reservoir 11 is formed below the container 8. ing.

The scroll compressor section 9 includes an orbiting scroll 13, a fixed scroll 12, a drive shaft 16 serving as crank oil driven by an electric motor 10, a frame 14, and a rotation preventing mechanism 40.

The orbiting scroll 13 has a spiral wrap 13a on a head plate 13b.
Having. A first bearing 19 into which the crank portion 16a of the drive shaft 16 is inserted is provided on the back surface of the end plate 13b.
3b is provided with a pressure guiding hole 13c that communicates the space of the wrap 13a during compression with the intermediate pressure chamber 22.

The fixed scroll 12 fixed to the container 8 also has a head 12
A spiral wrap 12a is provided on b. Further, a suction hole 41 is provided in the outer periphery of the lap, and a discharge hole 23 is provided in the center of the lap.

A second bearing 17, a third bearing 47, and a thrust bearing 25 for supporting the drive shaft 16 are installed on a frame 14 fixed to the container 8, and a pedestal 42 for clamping the orbiting scroll 13 between the fixed scroll 12 and the thrust bearing 25. Further, an intermediate pressure chamber 22 for applying an 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 turning movement of the orbiting scroll 13, the center of the oil supply hole 43f makes a turning movement with the same radius as the crank radius of the crank 16a, that is, the turning radius of the orbiting scroll. Oil filling hole 43
The length obtained by adding the radius of the hole of f and the radius of the oil supply hole 43d is equal to or greater than the radius of the turning motion of the oil supply hole 43f.
During the orbiting movement of the orbiting scroll 13, the oil supply holes 43f and 43d are always connected to each other.

The second bearing 17 is a roller bearing composed of an outer ring, an inner ring, a roller, and the like. A thrust bearing is provided at an end of the inner ring on the electric motor side to receive a slicing force applied to the crankshaft. A groove is provided on the surface of the thrust bearing 25. Third bearing
An axial groove 26 is provided on the surface of the crankshaft 16 that slides with the shaft 18 in the same manner as shown in FIG. 3, and the axial groove extends from the vicinity of the motor-side end of the third bearing 47 to the third end. The bearing 47 is provided in communication with a space formed between the frame 14 on the compressor side and the crankshaft 16. Also, the crankshaft 16 communicates with a lubrication hole 43a, which is provided at the center of the crankshaft 16 and is not open at the motor-side shaft end, near the motor-side end of the axial groove provided on the crankshaft. It has become.

Next, the operation of the scroll compressor will be described.
When the drive shaft 16 is rotated by the electric motor 10, the orbiting scroll 13 orbits without rotating by the rotational movement of the crank 16a and the action of the rotation preventing mechanism 40. As a result, the wraps 12a of the orbiting scroll 13 and the fixed scroll 12
The space formed by 13a and the end plates 12b, 13b moves to the center and reduces its volume, compresses the gas sucked through the suction hole 41 and discharges it through the 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.
After cooling the electric motor 10 through the discharge pipe 46, it is 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 from acting. To prevent this, the intermediate pressure chamber 22 on the back of the orbiting scroll is used.
The internal pressure is maintained at a pressure lower than the discharge pressure and higher than the suction pressure (intermediate pressure) by the pressure guiding holes 13b. Therefore,
An intermediate pressure portion 43g is formed between the end of the third bearing 47 on the compression mechanism side, that is, between the second bearing and the third bearing, and the intermediate pressure portion 43g is slightly higher than the pressure of the intermediate pressure chamber 22. The state is the pressure _Pm1 , and the motor-side end is in the discharge pressure _Pd state.

As a result, the end faces of the orbiting scroll bearing 19 and the second bearing 17 of the frame on the side of the intermediate pressure chamber 22 are maintained at the above-mentioned intermediate pressure. And an oil supply hole 43 provided in the orbiting scroll
e and 43f are guided in a discharge pressure state to the end of the oil supply hole 43a of the drive shaft, the oil supply hole 43a is filled with oil, and the pressure difference between the discharge pressure and the intermediate pressure is further increased through the oil supply hole 43b. Accordingly, the third bearing 47 is supplied with oil. After lubricating the third bearing 26,
The thrust bearing 25 is moved between the intermediate pressure _Pm1 and the roller pressure _Pm2.
(P _m1> P _m2) of the intermediate pressure chamber and lubricated by the pressure difference of the pressure P _m of the pressure P _{m @ 2} and the intermediate pressure chamber of the roller portion of the second bearing 17 by the differential pressure (P _m2> P _m) 22 Flows into The bearing 19 is supplied with oil by an oil fed to the end face thereof through an oil supply hole 43f by a differential pressure between the discharge pressure and the intermediate pressure, and 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, and is discharged into the closed container 8 through a discharge port provided at the center of the fixed scroll 12 while being mixed with the refrigerant gas. Collected at 11.

The orbiting scroll 13 and the fixed scroll 12 wrap with each other.
Combined with 12b and 13b facing inward, fixed scroll 1
The orbiting scroll 13 is held between the base 2 and the base 42 of the frame 14. A rotation prevention mechanism 40 for preventing rotation of the orbiting scroll is provided 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. An oil supply hole 43a is provided in the drive shaft 16.
It is provided on 16 rotation centers. One end of the oil supply hole 43a is open to the end face of the crank portion 16a, and the oil supply hole 43b
It is open to the bearing 18 via.

Inside the end plate 12b of the fixed scroll 12, an oil supply hole 43c communicating with the oil sump 11, and an opening at a portion where the end plate 13b of the orbiting scroll 13 and the end plate 12b of the fixed scroll 12 sliding with the oil supply hole 43c slide. An oil supply hole 43d is provided. Further, in the base plate 13a of the orbiting scroll 13, an oil supply hole 43e for communicating the end face of the bearing 19 and the outer periphery of the end plate 13b is provided, and the outer end of the oil supply hole 43e is closed with a screw 44. Oiling hole 43e
Has an inner end facing an oil supply hole 43a in the drive shaft 16.
The oil supply hole 43e and the oil supply hole 43d in the fixed scroll 12 are provided in a sliding portion of the end plate 13b with the end plate 12b of the fixed scroll 12.
And an oil supply hole 43f that communicates with

With the above-described configuration, even in the inverter-driven horizontal scroll compressor, first, oil supply to all the bearings of the second bearing 17, the third bearing 47, and the thrust bearing 25 is performed by the discharge pressure, the intermediate pressure, and the discharge pressure. Therefore, a sufficient flow rate of oil can be supplied to each bearing even when the operating speed of the compressor is low, so that wear and seizure of the bearings can be prevented.

Further, as described above, the flow path resistance of each bearing may be determined from the oil flow rate to obtain the required oil film thickness and the cooling amount under the strictest bearing conditions within the set compressor speed range. Thus, wear and seizure of the bearing can be prevented in the entire operation range.

Second, a bearing structure for supporting the crankshaft 16 is provided as a second bearing.
Since it is structured to be supported by two of the bearing 17 and the third bearing 47 and refueled only by differential pressure lubrication, a hole for draining oil in the frame or a spiral groove for draining oil in the third bearing is machined. Since there is no need and the number of bearings can be reduced, there is an effect that an inexpensive bearing configuration can be obtained.

Further, an oil discharging mechanism as shown in FIG. 4 may be provided in the frame 14 of the intermediate pressure chamber so as to discharge the oil to the oil sump 11 side.
Thereby, the oil stirring loss due to the balance weight can be reduced.

Third, by using a horizontal scroll compressor,
Due to the positional relationship between the compressor and the heat exchanger in the air conditioner, the mountability is improved, and the size of the air conditioner is reduced.

〔The invention's effect〕

According to the present invention, all of the first bearings have a bearing structure in which lubrication is performed by the differential pressure between the discharge pressure and the intermediate pressure, so that a substantially constant lubrication amount is applied to the bearings regardless of the rotational speed of the compressor. Since the oil can be supplied, a sufficient amount of lubrication can be ensured even in a low speed operation range, and there is an effect that bearing wear and seizure can be prevented.

Second, a bearing structure for supporting the shaft portion 16a of the crankshaft 16 is supported by two of a second roller bearing 17 and a third slide bearing 18, and the bearing is lubricated only by the differential pressure lubrication. With the structure, there is no need to machine a hole for oil discharge in the frame or a spiral groove for oil discharge in the third bearing, and the number of bearings can be reduced, so that an inexpensive bearing configuration is obtained.

Thirdly, since the flow path resistance of the oil supply path is set so that the oil supply amount can be secured under the strictest conditions in the set rotational speed range, there is an effect that wear and seizure of the bearing can be prevented in the entire operation range. .

Further, by providing the oil draining mechanism in the frame of the intermediate pressure chamber, the loss of oil agitation due to the balance weight can be reduced, and there is an effect that an efficient compressor can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a cycle configuration equipped with an inverter,
FIG. 2 is a longitudinal sectional view showing the structure of a vertically mounted hermetic scroll compressor according to one embodiment of the present invention, FIG. 3 is an enlarged sectional view of a bearing portion of FIG. 2, and FIG. FIG. 5 is an enlarged sectional view of a bearing portion of another embodiment, and FIG. 5 is a longitudinal sectional view showing the structure of a horizontally mounted hermetic scroll compressor according to another embodiment of the present invention.
FIG. 6 is an enlarged sectional view of a refueling portion. 1 Scroll compressor 2,3 Heat exchanger 4 Expansion valve 5 Four-way valve 6 Inverter drive 7
... Computer, 8 ... Closed container, 9 ... Compressor part, 10
…… Electric motor, 11… Puddle, 12 …… Fixed scroll, 13
… Orbiting scroll, 12a, 13a… lap, 12b, 13b…
End plate, 14 …… Frame, 16 …… Crankshaft, 17 …… Second
Bearing, 18 ... third bearing, 19 ... first bearing, 20 ...
Refueling passage, 20a ... Intermediate pressure section, 21 ... Refueling device, 22 ...
Intermediate pressure chamber, 25 thrust bearing, 26 axial groove, 27
... Oil holes, 43a, 43b ... Oil holes, 43c, 43d, 43e, 43f ... Oil holes, 43g ... Intermediate pressure part, 45 ... Path, 47 ... Third bearing.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-61-178589 (JP, A) JP-A-63-29083 (JP, A) JP-A-59-115488 (JP, A) JP-A-62 58094 (JP, A) Japanese Utility Model Showa 62-110593 (JP, U) Japanese Utility Model Showa 60-171985 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F04C 18/02 F04C 29 / 02

Claims (6)

(57) [Claims] 1. A fixed scroll, an orbiting scroll meshed with the fixed scroll, a crankshaft engaged with the orbiting scroll, a plurality of bearings for supporting the crankshaft on a frame, and a drive shaft for driving the crankshaft. A speed change motor, a hermetic container for accommodating these in a sealed space where discharge pressure acts, lubricating oil supply means for supplying lubricating oil stored in the hermetic container to the plurality of bearings, an orbiting scroll and a fixed scroll A gas in the compression chamber in the middle of compression formed by the intermediate scroll chamber is provided with an intermediate pressure chamber on the back of the orbiting scroll for applying an intermediate pressure between the discharge pressure and the suction pressure. A first bearing is provided at an engagement portion between the orbiting scroll and the crankshaft in the room, and the crankshaft is connected to a second roller provided on a side close to the orbiting scroll. Receiving and a thrust bearing between the second roller bearing and the frame, and supported by the frame at a third sliding bearing provided on the side close to the motor, the second bearing and the third
Between the bearing and the intermediate pressure chamber to form an intermediate pressure portion,
The lubricating oil supply means has a first oil supply passage having one end communicating with the lubricating oil in the closed container and the other end opening to the intermediate pressure chamber, an oil supply hole branched from the first oil supply passage, The intermediate pressure portion communicates with the intermediate pressure portion through an axial groove formed in the crankshaft corresponding to the third bearing, and furthermore, an intermediate pressure chamber through an oil passage in the thrust bearing portion and the second roller bearing. A second oil supply passage communicating with the scroll fluid machine. 2. A fixed scroll, a revolving scroll engaged with the revolving scroll, a crankshaft engaged with the revolving scroll, a plurality of bearings supporting the crankshaft on a frame, and a drive shaft for driving the crankshaft. A speed change motor, a hermetic container for accommodating these in a sealed space where discharge pressure acts, lubricating oil supply means for supplying lubricating oil stored in the hermetic container to the plurality of bearings, an orbiting scroll and a fixed scroll A gas in the compression chamber in the middle of compression formed by the intermediate scroll chamber is provided with an intermediate pressure chamber on the back of the orbiting scroll for applying an intermediate pressure between the discharge pressure and the suction pressure. A first bearing is provided at an engagement portion between the orbiting scroll and the crankshaft in the room, and the crankshaft is connected to a second roller shaft provided on a side close to the orbiting scroll. And a thrust bearing between the second roller bearing and the frame, and at least one third sliding bearing provided on the side closer to the motor, supporting the frame with the lubricating oil means. A first oil supply passage communicating with the lubricating oil therein, the other end of which is open to the intermediate pressure chamber, an oil supply hole branched from the first oil supply passage, and the oil supply hole provided to the motor of the third bearing. A required maximum lubricating flow rate within a set rotation speed range, wherein the opening is opened at a bearing end on the near side, and the opening and an intermediate pressure portion communicated with the intermediate pressure chamber between the second bearing and the third bearing are connected. A scroll fluid machine having a second oil supply passage having a cross-sectional area capable of supplying the oil through the second bearing and communicating through the second bearing. 3. The scroll fluid machine according to claim 1, wherein said second bearing is a rolling bearing. 4. The scroll fluid machine according to claim 1, wherein an oil feed mechanism for feeding oil from said intermediate pressure chamber into said closed vessel is provided on a frame forming said intermediate pressure chamber. 5. The scroll fluid machine according to claim 4, wherein the fixed scroll and the orbiting scroll are arranged at an upper part, and the motor is arranged at a lower part. 6. The scroll fluid machine according to claim 1, wherein said crankshaft is arranged in a direction perpendicular to the direction of gravity.