JPH0571486A - Lubricating device for hermetic two-stage scroll compressor - Google Patents

Abstract

(57) [Summary] [Structure] Discharge pipe 1 provided below the low-stage compressor 14.
c is connected to the suction part 1d of the high-stage compressor 15 by a pipe 16, and the discharge pipe 1c 'provided in the lower part of the high-stage compressor 15 is connected to a separate oil sump container 17 and a pipe 18. .. One of the oil accumulated in the lower portion of the oil sump container 17 is an oil passage 11 b provided in the cover 11 of the low-stage compressor 14.
Is connected to the oil supply pipe 19 via the expansion device 20, and the other is connected to the oil passage 1 provided in the cover 11 of the high-stage compressor 15.
1b is connected to the oil supply pipe 20. [Effect] The electric motor is efficiently cooled, oil is prevented from rising to the cycle, and oil is reliably supplied to the bearings and sliding parts of the compressor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hermetic two-stage scroll compressor, and more particularly to an oil supply device for a sliding portion of a compressor.

[0002]

2. Description of the Related Art The oil supply structure of a hermetic scroll compressor is
It is disclosed in JP-A-58-214690 and JP-A-61-87994.

Conventionally, in the oil supply method of this type of hermetic scroll compressor, oil is accumulated in the lower part of the hermetic container and the oil is supplied through an oil supply hole provided in the crankshaft. Further, in the vertical compressor, the electric motor is provided in the lower portion, and the discharge connection portion is provided in the space portion between the compression mechanism portion and the electric motor.

[0004]

In the above conventional compressor, oil is stored in the lower part of the electric motor, and when the oil amount is large or when the discharge pressure decreases, the refrigerant in the oil foams and the oil level is Since the temperature rises, the rotor of the electric motor stirs the oil to increase the power, and the stirrer causes the foamed oil to be supplied to the bearing, causing the bearing sliding portion to run out of oil film and seizing the bearing.

The compressor is a single-stage compressor,
When these compressors are connected in series to form a two-stage compressor, oil moves from the low-stage side compressor to the high-stage side compressor, and the low-stage side compressor runs out of oil, causing the bearing to seize. ..

An object of the present invention is to provide a structure in a two-stage compressor using two scroll compressors, which reliably supplies oil to the bearings and sliding parts of each compressor.

[0007]

DISCLOSURE OF THE INVENTION The present invention relates to two scroll compressors in which a hermetically sealed container houses therein a compression mechanism portion comprising an orbiting scroll, a fixed scroll, an Oldham ring, a frame and the like, an electric motor and a drive shaft for connecting the two. Are connected in series, and a discharge connection is provided at the bottom of each compressor so that oil does not collect.

[0008] The discharge connection portion of the high-stage compressor and a separate oil reservoir container are connected to store oil in the closed container, and the oil is supplied to the oil supply holes provided on the end faces of the drive shafts of the respective compressors on the electric motor side. By providing the passage for supplying oil from the separate oil sump container, oil is supplied from the separate oil sump container to the bearing of each compressor via the oil supply hole in the drive shaft.

[0009]

The discharge section of the low-stage compressor and the suction section of the high-stage compressor are connected by piping. The discharge section of the high-stage compressor and the separate oil sump container are connected by piping.
The oil in the low-stage and high-stage compressors is separated into gas and oil by the oil sump container, and the oil is accumulated in the lower part.

Since the oil in the oil sump container is connected to the oil supply hole provided in the end surface of the drive shaft of each compressor by the pipe and communicates with the oil supply hole in the drive shaft, the difference in pressure causes It is guided to the oil supply hole in the drive shaft, and oil is supplied to each bearing and sliding portion.

Further, a throttle portion is provided in the middle of the oil passage of the oil reservoir that is separate from the end surface portion of the drive shaft of the low-stage compressor, and is substantially equal to the discharge pressure of the low-stage compressor. I am doing it.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a vertical sectional view showing the overall structure of a low-stage and high-stage vertical refrigeration scroll compressor according to an embodiment of the present invention. In FIG. 1, a scroll compression mechanism 2 and an electric motor 3 for driving the scroll compression mechanism 2 are housed in an airtight container 1, and a space 4 is formed in the lower portion.

The scroll compression mechanism 2 comprises an orbiting scroll 5, a fixed scroll 6, a drive shaft 7 forming a crankshaft driven by an electric motor 3, a frame 8 and a rotation preventing mechanism 9.

The orbiting scroll 5 has a spiral wrap 5b on a base plate (end plate) 5a. Further, a bearing 5c into which the crank pin portion 7a of the drive shaft 7 is inserted is provided on the back surface of the base plate 5a, and the base plate 5a has a pressure equalizing hole 5d for communicating the lap 5b space during compression and the back pressure chamber 8c. Is provided.

Fixed scroll 6 fixed to frame 8
Also has a spiral wrap 6b on the base plate 6a.

A suction hole 6c is provided on the outer periphery of the wrap, and a discharge hole 6d is provided at the center of the wrap.

The frame 8 fixed to the container 1 has bearings 8a, 8a 'for supporting the drive shaft 7, a base 8b for holding the orbiting scroll 5 with the fixed scroll 6, and an appropriate pressing force for the orbiting scroll 5. A back pressure chamber 8c for giving is provided.

The orbiting scroll 5 and the fixed scroll 6 are combined with each other with the wraps 5b and 6b facing inward, and the fixed scroll 6 and the pedestal 8b of the frame 8 hold the orbiting scroll 5 therebetween. A rotation prevention mechanism 9 for preventing rotation of the orbiting scroll is installed between the rear surface of the orbiting scroll and the frame. One end of the drive shaft 7 is the bearing 5
It has a crank pin 7a supported by c. An oil supply hole 7c is provided in the drive shaft 7 on the center of rotation of the drive shaft 7. One end of this oil supply hole 7c is opened to the end face of the crank pin 7a, the other end is opened to the end part of the bearing 11a provided on the cover 11, and the bearings 8a, 8 are provided through the oil supply hole 7f.
It opens at a '.

The cover 11 is a bearing 1 for supporting the drive shaft 7.
1a, an oil passage 11b for guiding oil from a separate oil sump container 10
Is provided, and is fastened to the frame 8 together with the electric motor 3 with bolts 13.

Further, the bearing 11a is provided with a spiral oil groove 11c for generating a lift toward the electric motor 3 side.

Next, the operation of the scroll compressor will be described. When the drive shaft 7 is rotated by the electric motor 3, the orbiting scroll 5 makes an orbiting motion without rotating due to the rotational motion of the crank pin 7a and the action of the rotation preventing mechanism 9.
As a result, the space formed by the orbiting scroll 5 and the wraps 5b, 6b of the fixed scroll 6 and the base plates 5a, 6a is moved to the center and its volume is reduced, and the gas sucked from the suction hole 6c is compressed and discharged. Discharge from the hole 6d. The discharged gas is used for the base plate 6a of the fixed scroll 6 and the frame 8
After the electric motor 3 is cooled through the passage 12 formed in the above, it is discharged from the discharge pipe 1c. When the scroll performs a compression action, a force for separating the orbiting scroll 5 and the fixed scroll 6 acts. Therefore, in order to prevent this, the pressure in the back pressure chamber 8c on the back surface of the orbiting scroll is adjusted by the pressure equalizing hole 5d. ,
Pressure lower than discharge pressure but higher than suction pressure (intermediate pressure)
Kept in.

As a result, the end surfaces of the bearing 5c of the orbiting scroll and the bearing 8a 'of the frame on the back pressure chamber 8c side are kept at the intermediate pressure.

FIG. 2 shows the oil supply system of the two-stage compressor. The discharge part 1 c provided at the lower part of the low-stage compressor 14 is connected to the suction part 1 d of the high-stage compressor 15 by a pipe 16. Discharge part 1c 'provided under the high-stage compressor 15
Is connected to a separate oil sump container 17 and a pipe 18.

The discharge refrigerant in the oil sump container 17 and the oil are separated from each other. The oil is accumulated in the lower portion and the refrigerant is introduced into the refrigeration cycle from the upper portion. The oil accumulated in the lower portion of the oil sump container 17 is connected via an oil passage 11b provided in the cover 11 of the low-stage compressor 14, an oil supply pipe 19 and a throttle device 20. Further, the oil passage 11 b provided in the cover 11 of the high-stage compressor 15 is connected to the oil supply pipe 21. The oil sump container 17 is in the discharge pressure state of the high-stage compressor 15. As described above, the inside of the oil supply hole 7c of the drive shaft 7 of the low-stage compressor 14 communicates with the oil sump container 17 via the oil supply pipe 19 and the expansion device 20. It is filled with oil that has been depressurized to the discharge pressure. On the other hand, the drive shaft 7 of the high-stage compressor 15
The inside of the oil supply hole 7c is similarly oiled without passing through the expansion device 20, and is substantially filled with the oil in the discharge pressure state of the high-stage compressor 15. Since the back pressure chamber side end surface of the orbiting scroll of each compressor and the bearing of the frame has an intermediate pressure of each compressor, the bearing sliding surface is oiled by the differential pressure.

Although the throttle device is connected to the oil supply pipe 18 in the above embodiment, it may be provided in the oil passage 11b provided in the cover.

FIG. 3 shows a partially enlarged view of another embodiment which communicates with a separate oil reservoir and an oil supply hole provided in the end surface of the drive shaft on the electric motor side.

On the electric motor 3 side of the oil supply hole 22c in the drive shaft 22, there is provided a press-in hole 22d for the oil-supply pipe 23.
A slide bearing 22e is provided at d. The oil supply pipe 23 is pushed in with a gap in which the drive shaft 22 is movable in the axial direction. On the other hand, the other end of the oil supply pipe 23 has a base 2
4 is in communication with a spherical plain bearing 25. The operation is the same as above.

In the above embodiment, the so-called vertical scroll compressor in which the scroll compression mechanism and the drive shaft for driving the scroll compression mechanism are arranged vertically has been described. However, the so-called horizontal scroll compressor in which the drive shaft is horizontally arranged in the closed container is described. The present invention can be easily applied to a scroll compressor.

[0029]

According to the present invention, the discharge gas discharged from the compression mechanism portion is discharged from the closed container after passing through the electric motor, so that the electric motor can be cooled efficiently.

Further, since the oil in the closed container is discharged together with the discharge gas and is transferred to a separate oil sump container, the electric motor is not immersed in the oil and the power is not increased by stirring the oil. Also, since the oil in the discharge gas is separated by the separate oil sump container, the oil rises to the cycle is reduced and the lubrication to the bearings and sliding parts of the compressor is ensured.

[Brief description of drawings]

FIG. 1 is a sectional view showing the overall structure of a vertical hermetic scroll compressor according to an embodiment of the present invention.

FIG. 2 is a refueling system diagram of the present invention.

FIG. 3 is a partial cross-sectional view of another embodiment that communicates with a separate oil sump container and an oil supply hole provided in an end surface of the drive shaft on the electric motor side.

[Explanation of symbols]

1 ... airtight container, 2 ... scroll compression mechanism, 3 ... electric motor,
5 ... Orbiting scroll, 6 ... Fixed scroll, 7, 21 ...
Drive shaft, 8 ... Frame, 11 ... Cover, 14 ... Low-stage compressor, 15 ... High-stage compressor, 16, 18 ... Piping, 17 ...
Oil sump container, 19, 21 ... Oil supply pipe, 20 ... Throttling device,
22 ... Oil supply pipe, 23 ... Pedestal, 24 ... Spherical bearing.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mutsunori Matsunaga 390 Muramatsu, Shimizu City, Shizuoka Prefecture Hitachi Ltd. Shimizu Plant

Claims (1)

[Claims] 1. A low-stage side in which a compression element including a fixed scroll and an orbiting scroll and an electric motor are housed in a closed chamber, a crank portion of a drive shaft is connected to the orbiting scroll, and a drive shaft shaft portion is supported by a frame. An oil sump container that includes a compressor and a high-stage compressor, connects the discharge part of the low-stage compressor and the suction part of the high-stage compressor, and is separate from the discharge part of the high-stage compressor. And an oil passage communicating with an oil reservoir and an oil supply hole provided in the end face of the drive shaft on the electric motor side, and oil is supplied at a differential pressure to supply oil to a hermetic two-stage scroll compressor. apparatus.