JPH0431684A - Closed scroll compressor - Google Patents

Abstract

PURPOSE:To enhance oiling performance by allowing the pressure of a back pressure chamber within a closed container to be first intermediate pressure, allowing pressure within the closed container to be second intermediate pressure, and thereby oiling to respective bearings and respective sliding sections based on the difference in pressure between the high pressure of an oil bank and aforesaid intermediate pressure. CONSTITUTION:When a horizontal turning scroll 8 is in operation, oil is supplied from a back pressure chamber 9 and an electric motor housing chamber 3 in order that the occurrence of oil leak out of tooth spaces is prevented, and sliding surfaces are lubricated, and oil contained in cooling medium is separated out of cooling medium by an oil separator 4 provided outside, so that separated oil is stored in a lower oil bank 12. In this place, during the period of time from the completion of suction to discharge at the compression section, the tooth spaces are communicated with the back pressure chamber 9 through a small diameter hole 14, so that the pressure of the back pressure chamber 9 is made to be first intermediate pressure. On the other hand, a passage 13 is provided, which communicates the tooth spaces just after the completion of suction by the compression section 2 with the electric motor housing chamber, so that the pressure of the electric motor housing chamber is made to be second intermediate pressure. And oil is allowed to flow based on the difference in pressure between high pressure within the oil bank 12 and aforesaid intermediate pressure, so that bearings 19, 20 and 23 are thereby lubricated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention maintains the compression mechanism at a first intermediate pressure and sets the electric motor storage chamber at a second intermediate pressure, or
The present invention relates to the structure of a hermetic scroll compressor for refrigeration, in which first and second intermediate pressure chambers are communicated with each other and one of the intermediate pressures is set.

[Conventional technology]

The structure in which the motor storage chamber is set at an intermediate pressure between the suction pressure and the discharge pressure and is cooled by injection is based on Japanese Patent Application Laid-Open No. 57-1958.
There is a conventional example described in Japanese Patent No. 88. However, this conventional hermetic scroll compressor has the following problems. First of all, the oil sucked or supplied into the compression chamber is discharged outside the closed container, returns to the suction pipe through the refrigeration cycle, and does not return from the intermediate pressure introduction pipe. It is not possible to form an oil sump under pressure. Furthermore, it circulates within the refrigeration cycle. The amount of oil (the amount of oil coming up) gradually increases, making it impossible to form an oil cycle for the sliding parts including the bearings inside the compressor. In addition, the inside of the casing has a discharge pressure, and the pressure in the back pressure chamber, which is between the suction pressure and the discharge pressure, holds the compression mechanism by bringing the orbiting scroll and fixed scroll into close contact with each other, and also maintains the pressure between the discharge pressure and the intermediate pressure. An example of a structure for differentially lubricating the sliding parts is described in Japanese Patent Publication No. 37238/1983. However, in this conventional device, the casing needs to be thick enough to withstand high pressure, which increases the weight and increases the cost. In addition, since the electric motor is cooled with discharged gas, it is used at high temperatures.
It is necessary to improve the grade of motor insulation. Furthermore, when the temperature increases, the winding resistance increases and the motor efficiency decreases. The high-pressure method has some drawbacks, such as the fact that it has to be used in this condition.

[Problem to be solved by the invention and means for solving the problem]

The conventional technology of Arata (Japanese Patent Application Laid-Open No. 57-195888) does not take into consideration oil recovery means and oil supply method for each bearing against oil rise, and oil is stably maintained in the compressor as the amount of oil rises. This makes it impossible to supply oil to the bearing. Furthermore, the motor side bearing had a slight differential pressure, and the oil supply was also related, resulting in unstable oil supply.

The purpose of the present invention is to maintain an intermediate pressure inside the sealed container, discharge the discharged gas and the oil contained in the discharged gas directly to the outside of the sealed container from the compression part, and separate the oil and refrigerant gas by an externally installed oil separator. The oil sump is connected to the oil supply system of the compressor by external piping, and the back pressure chamber inside the sealed container is set to a first intermediate pressure, and the inside of the sealed container is set to a second intermediate pressure, which is connected to the high pressure in the oil sump. The purpose is to supply oil to each bearing and all sliding parts using a pressure difference.

[Effect]

Gas that is being compressed is guided through small holes into a space surrounding the orbiting scroll and surrounded by the fixed scroll, frame, and crankshaft, thereby forming a back pressure chamber having a first intermediate pressure.

An injection pipe is connected to the motor storage chamber and communicated with a compression chamber that is not connected to suction, so that the motor storage chamber is brought to a second intermediate pressure. The motor is cooled by injecting refrigerant gas into the motor storage chamber. This refrigerant is recovered into the compression chamber, and during this recovery, the oil discharged into the motor storage chamber can also be recovered at the same time. Since the refrigerant recovery passage is formed of a compression chamber that does not communicate with the suction, a drop in cooling power does not occur, and this communication passage allows the second intermediate pressure in the motor storage chamber to be stabilized.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. 1st
The figure shows a horizontal compressor. In a hermetic scroll compressor that maintains an intermediate pressure (between high pressure and low pressure, close to low pressure) inside the hermetic container 1, the flow of refrigerant gas is the refrigerant sucked from outside the compressor through the suction pipe 5 that penetrates the hermetic container. The gas contains low-temperature, low-pressure refrigerant gas and a very small amount of oil returned from the refrigeration cycle. This refrigerant gas immediately enters the tooth gap between the fixed scroll 7 and the orbiting scroll 8 by opening the check valve 6 and by the orbiting movement of the orbiting scroll.

Reduce volume. At this time, oil is supplied from the back pressure chamber 9 and the motor storage chamber 3 for the purpose of oil recovery, prevention of tooth groove leakage, and lubrication of sliding surfaces. When the refrigerant gas reaches a predetermined pressure, it is discharged from a discharge pipe 1o that passes through the closed container. This high-pressure refrigerant gas contains oil, and the oil and refrigerant gas are separated in an externally installed oil separator 4, and the refrigerant gas flows to a condenser in the refrigeration cycle. On the other hand, the oil separated in the oil separator becomes oil droplets and accumulates in the oil reservoir 12 at the bottom. Next, the tooth gap between the completion of suction and discharge of the compression part and the back pressure chamber 9 are communicated through a small diameter hole 14 to form a back pressure chamber 9 having a first intermediate pressure. In addition, in a similar manner, a passage 13 is provided which communicates the tooth groove of the compression part 2 immediately after suction is completed with the electric motor housing chamber, and this passage sets the electric motor housing chamber to an intermediate pressure that is a second intermediate pressure.

The motor housing chamber is maintained at a second intermediate pressure close to the low pressure due to the passage with the compression part tooth groove. A pipe 16 is provided that penetrates the electric motor storage room and the sealed container, and this pipe is used to evaporate a part of the condensate from the air condenser or to guide the refrigerant gas after evaporation from the supercooler. ) to cool the electric motor 17. Next, the oil cycle in the compressor will be explained. From the high-temperature, high-pressure oil reservoir 12, the oil is led to the bearings 19 and 20 in the motor storage chamber through an oil supply pipe 18 that penetrates the closed container. Since the electric motor storage chamber 3 and the back pressure chamber 9 are both at intermediate pressure, the oil flows due to the pressure difference between the high pressure and the intermediate pressure, and lubricates the bearing 19 and the bearing 2o, as well as the cut hole provided in the shaft 21. 22 lubricates the orbiting scroll bearing 23. Waste oil after each bearing lubrication is discharged from the bearing 19 to the motor storage chamber 3, and from the bearings 2o and 23 to the back pressure chamber 9. The oil discharged into the motor storage chamber enters the compression section through the passage 13 and is discharged together with the refrigerant gas that cooled the motor. On the other hand, the oil discharged into the back pressure chamber 9 lubricates the Oldham ring 15, and a part of it enters the compression section through the hole 14 and is discharged. Other waste oil lubricates the mirror plate surface 14, flows into the tooth groove on the suction side, and is discharged together with the refrigerant gas. All the oil that has lubricated each sliding part in this way flows into the tooth groove of the compression part, is collected and discharged together with the refrigerant gas, and is sent to the oil separator 4.
This is an oil cycle in which the oil is separated in the oil reservoir 12, and then oil is supplied to each sliding part again. Next, a method for introducing refrigerant liquid or gas to the compressor pipe 16 for cooling the motor will be explained. The high-temperature, high-pressure refrigerant gas discharged from the compressor is condensed into medium-temperature, high-pressure refrigerant liquid in the condenser 25.

This liquid refrigerant passes through the main expansion valve 26, enters the evaporator 27, becomes a low-temperature, low-pressure refrigerant gas, and is sucked into the compressor.In a so-called general refrigeration cycle, a part of the condensed liquid refrigerant is branched off and auxiliary. The expansion valve 28 generates a low-temperature, medium-pressure refrigerant liquid or gas, which flows through the pipe 29 and is injected from the pipe 16 of the compressor. Another method is to inject evaporated gas from a supercooler (not shown) through a pipe 16 of a compressor. Next, when the compressor is stopped, the check valve 6 is immediately closed, and since the suction side has a small volume, the pressure immediately rises to prevent reverse rotation.

Therefore, since the inside of the sealed container is maintained at an intermediate pressure, the bearings 19, 20, and 23 are supplied with oil from the passage 18 due to the pressure difference between the oil separator 4 and the motor storage chamber 3, and the oil in the oil sump 12 is
It may move to the motor storage chamber 3 and back pressure chamber 9. In order to prevent this, a blocking valve 30 is provided in the oil supply pipe 18.

Similarly, a blocking valve 31 is provided in the pipe 29, which is a liquid injection pipe for cooling the motor. In addition, a check valve 32 is provided between the discharge pipe 10 and the oil separator 4 to prevent refrigerant gas or oil from flowing in and out of the closed container, thereby maintaining the inside of the closed container at an intermediate pressure.

In this way, the refrigerant gas cycle and oil cycle formed a refrigeration cycle. In addition, although the horizontal compressor is described in this figure, a vertical expansion compressor can also be constructed in the same manner. According to this embodiment, (1) all the bearings and sliding parts were lubricated by the differential pressure between the high pressure and the intermediate pressure, and the reliability of the bearings and sliding parts was ensured;

■Since the electric motor is cooled with refrigerant, it can always be used at low temperatures. ■Since the inside of the closed container has an intermediate pressure, it was possible to make the wall thinner.

Another embodiment will be explained with reference to FIGS. 2 and 3. Figures 2 and 3 show a twin scroll compressor.

FIG. 2 shows two compression mechanisms 33 and 34 inside the closed container 1.
This allows each compression mechanism section to operate independently, expanding the capacity control range and capacity, and improving the organization of the compressor. It has the same action and effect as in Fig. 1. Detailed explanation will be omitted. Further, although the pipe 16 for introducing the liquid refrigerant, the blocking valve, and the like are combined into one system, it is possible to use two systems for each compression mechanism section, if necessary.

FIG. 3 shows a configuration in which two compressors are installed in parallel in FIG. 1. Each compressor can be operated independently, with the aim of expanding capacity control range and capacity.

The number of compressors can be any number from two to more. This embodiment also has the same functions and effects as those in FIG. 1, so detailed explanation will be omitted.

〔Effect of the invention〕

According to the present invention, since the back pressure chamber can be set to the first intermediate pressure and the motor storage chamber to the second intermediate pressure, each bearing and sliding surface can be lubricated by the pressure difference between the high pressure and the intermediate pressure. can do. All waste oil from each bearing and after oiling is collected in the compression chamber, separated and recovered by an external oil separator, and can be reconsolidated.

Furthermore, since the electric motor can be cooled by refrigerant cooling, by injecting an amount of refrigerant according to the operating conditions, the electric motor can be sufficiently cooled at a low temperature, and the electric motor can be used under conditions with good efficiency.

Furthermore, the casing can be made thinner and lighter.

Further, according to the structure of the present invention, since each bearing is lubricated by differential pressure, both vertical and horizontal structures are possible. This is advantageous when using a twin type compressor that compresses two compression mechanisms into the same casing, or when multiple compressors are arranged in parallel6.

[Brief explanation of the drawing]

FIG. 1 shows a refrigerant system diagram of a hermetic scroll compressor according to an embodiment of the present invention, and FIG. 2 shows a refrigerant system diagram of a hermetic twin scroll compressor in which the motor compartments of FIG. 1 are connected. FIG. 3 shows a refrigerant system diagram of a hermetic twin scroll compressor in which two compressors shown in FIG. 1 are connected in parallel. 3... Motor room, 4... Oil separator, 9... Back pressure chamber, 10... Discharge pipe, 13... Passage, 14... Hole,
16...Pipe, 18...Oil supply pipe, 22...Drill hole.

Claims (1)

[Claims] 1. In a hermetic scroll compressor in which a compression part and an electric motor of the scroll compressor are integrally housed in a hermetic container, an inlet pipe communicating with the outside of the hermetic container and a suction port of the compression part are connected, and an orbiting scroll and an electric motor are connected to each other. A first intermediate pressure is set in a chamber surrounded by a frame, and a second intermediate pressure is set inside the closed container by connecting the other introduction pipe communicating with the outside of the closed container and the compression section discharge port. Hermetic scroll compressor.