JPH06103039B2 - Scroll gas compressor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a scroll gas compressor.

2. Description of the Related Art A scroll compressor with low vibration and low noise characteristics has a suction chamber in the outer periphery and a discharge port in the center of the vortex winding, so that the flow of compressed fluid is unidirectional and the suction volume efficiency is high. well known.

However, especially in the case of compressing gas, it is necessary to make the dimensional accuracy of the vortex winding extremely high in order to reduce the leakage gap of the compression part, but the cost of the scroll compressor is reduced due to the complexity of the part shape and the dimensional variation. There was a problem that the performance was high and the performance was large.

Therefore, in order to solve this kind of problem, as is known from Japanese Patent Laid-Open No. 55-107093, the configuration shown in FIG.
As known from Japanese Patent Publication No. 95, the structure shown in FIG. 4 is invented, and a part of the lubricating oil supplied to the sliding portion is made to flow into the compression chamber together with the suction gas, and after the compression discharge, the lubricating oil is separated from the compressed gas. Based on the concept of returning to the space leading to the lubricating oil reservoir again later, in FIG. 3, after the compressed fluid is introduced into the oil separation tank 118 provided outside the compressor, the lubricating oil is stored in the oil separation tank 118. Was separated and returned through the capillary tube 117b into the closed container 112 at an intermediate pressure state between the discharge pressure and the suction pressure.

Further, in FIG. 4, the space in which the lubricating oil separated from the compressed gas in the cap 219 forms the suction passage through the holes 222 and 284.
It was configured to be returned to 280.

Problems to be Solved by the Invention However, as shown in FIG. 3, there is no distinction between compressed gas and lubricating oil, and the sealed container is in an intermediate pressure state through the capillary tube 117b.
In the configuration of returning to 112, when the compressed oil returns to the closed container 112 due to lack of lubricating oil, the viscosity is low, so the passage resistance is small, and a large amount of oil flows into the closed container 112, significantly reducing the compression efficiency, Further, when the oil separation tank 118 is provided with a function of returning only the lubricating oil, the cost is high and the oil separation tank 11
8 While it itself is large and requires a lot of installation space,
If the compressor operation is continued without returning the lubricating oil, the lubricating oil becomes insufficient, resulting in a decrease in compression efficiency and damage to the compressor.

Further, in the case where the oil return control mechanism as shown in FIG. 4 is not provided and the amount of lubricating oil is small, compressed gas easily passes through the holes 222 and 284, so that a large amount of compressed gas flows into the space 280 of the suction passage to improve compression efficiency. There was a problem of lowering it.

Therefore, the present invention provides a scroll gas compressor that discriminates a lubricating oil returning state and a compressed gas returning state from a temperature sensor and is inexpensive, highly efficient, and excellent in durability.

Means for Solving the Problems In order to solve the above problems, a scroll gas compressor according to the present invention has a low pressure side in which lubricating oil separated from compressed gas on the high pressure side is provided with a drive source of the compressor and a bearing portion of a main shaft. Alternatively, a fine oil return passage for returning to the intermediate pressure side of the low temperature atmosphere is provided, and the opening end of the oil return passage to the low pressure side or the intermediate pressure side is arranged on the low pressure side or the intermediate pressure side of the low temperature atmosphere to control the flow rate of the oil return passage. The temperature sensor linked to the control function of the compressor rotation speed is provided in close proximity to the temperature sensor.

Effect of the Invention With the above configuration, the present invention is a state in which an appropriate amount of lubricating oil is compressed and discharged together with the intake gas, and the lubricating oil separated from the compressed gas is continuously returned to the low pressure side or the intermediate pressure side of the low temperature atmosphere through the ultrafine oil return passage. In this case, the temperature rise of the temperature sensor is low and the compressor continues to operate, but for some reason the amount of lubricating oil that separates from the compressed gas decreases and compressed gas flows into the low pressure side or intermediate pressure side through the oil return passage. Then, the inflow of hot compressed gas increases and the temperature sensor rises to an abnormal temperature to shut off the oil return passage, throttle the oil return passage, stop the compressor, or increase / decrease the rotation speed to control lubricating oil. A reduction in compression efficiency due to a lack of lubricating oil, wear of sliding parts and seizure are prevented, resulting in high efficiency.
It is possible to provide a scroll gas compressor having excellent durability.

Embodiment A scroll gas compressor according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a vertical sectional view of a scroll gas compressor according to a first embodiment of the present invention, and FIG. 2 shows a vertical sectional view of a scroll gas compressor and an oil return passage control system according to a second embodiment of the present invention. FIG.

In FIG. 1, 1 and 2 are iron-made hermetically sealed cases, 3 is an iron frame, and its outer contact surface is welded and sealed together with the hermetically sealed cases 1 and 2 by a single weld bead 6, and the inside of the hermetically sealed cases 1 and 2 is discharged to the upper side. It is partitioned into a space 13 and a lower motor chamber 15 (low pressure side).

An orbiting scroll 10 is fitted in an eccentric hole 9 at the upper end of a drive shaft 8 which is rotatably driven by a motor 7 which is supported by a frame 3 and is controlled by an inverter power source (not shown), by engaging a rotation preventing component. A fixed scroll 11 having a discharge port 30 that meshes therewith is bolted to the frame 3.

The discharge space 13 formed by the closed case 1, the frame 3 and the fixed scroll 11 is a discharge pipe provided in the closed case 1.
The low-pressure side motor chamber 15 that communicates with the external piping system through 14 and is formed by the frame 3 and the hermetic case 2 communicates with the external piping system through the suction pipe 16 provided in the hermetic case 2. An oil sump 17 is provided at the bottom of the eccentric hole 9
The lower end of the drive shaft 8 having an eccentric oil hole 18 communicating with the oil reservoir 17 is embedded in the oil reservoir 17.

A temperature sensor 21 also serving as an overcurrent preventer for the motor 7 is attached to the upper coil end 20 of the motor 7, and a space between the discharge space 13 and the motor chamber 15 is opened at the bottom of a discharge space oil sump 22 to allow the frame 3 to be exposed. An oil return passage 31 which is provided and communicates with an ultra-fine passage 19 for returning the discharged oil and a nozzle 23 connected thereto communicates with each other, and the tip of the nozzle 23 is provided above the temperature sensor 21 so as to closely face each other.

A glass terminal 24 for electrically connecting the power supply device outside the compressor and the motor 7 is provided in the closed case 2 near the nozzle 23.

In addition, FIG. 2 shows that between the discharge space oil sump 22 and the motor chamber 15,
An oil return pipe 25 that opens to the bottom of the discharge space oil sump 22 and penetrates the closed case 1, a temperature sensor 21 provided outside the compressor.
External expansion device 26 and closed case 2
Through an oil return passage 31a passing through a nozzle 23a provided at an upper portion near the temperature sensor 21, and an oil cooling device 28 is provided in the middle thereof.

The operation of the hermetic scroll refrigerant compressor configured as described above will be described below.

In FIG. 1, when the drive shaft 8 is rotationally driven by the motor 7, the orbiting scroll 10 orbits, and after the refrigerant gas flows into the motor chamber 15 through the suction pipe 16, one of the lubricating oil contained in the refrigerant gas is discharged. Separated parts are confined in a compression chamber formed between the orbiting scroll 10 and the fixed scroll 11, compressed along with the orbiting movement of the orbiting scroll 10, and discharged from the discharge port 30 to the discharge space 13 to discharge refrigerant gas. Part of the lubricating oil contained therein is separated from the discharge refrigerant gas by its own weight and the like and collected in the discharge space oil sump 22,
After decompressing in the ultrafine passage 19, an appropriate amount is released from the tip of the nozzle 23 toward the temperature sensor 21 arranged in the motor chamber 15 in the low temperature atmosphere immediately below, and a part of the lubricating oil scattered is in the glass terminal 24. The water also splashes on the terminals and is finally collected in the oil sump 17 at the bottom. After being fed to the bearing sliding surface by the centrifugal pump action of the eccentric oil hole 18 of the drive shaft 8, it is compressed and discharged together with the suction refrigerant gas. It

On the other hand, the lubricating oil that has not been separated from the discharge refrigerant gas in the discharge space 13 is carried out to the external refrigeration cycle and returned to the compressor through the suction pipe 16 together with the suction refrigerant gas.

Lubricating oil having an appropriate viscosity in such a circulation cycle of the refrigerant gas and the lubricating oil has a function of lubricating the sliding portion and sealing a minute gap in the compression chamber, and contributes to stable operation of the compressor. If the oil sump 17 or the discharge space oil sump 22 runs short of lubricating oil (for example, if the piping of the refrigeration cycle is very long and the refrigerant speed in the piping is slow, such as when the compressor rotates at low speed, lubrication is performed). (The oil stays in the pipe and does not return to the compressor, causing a shortage of lubricating oil.)
Flow into the motor chamber 15 to rapidly increase the ambient temperature of the motor chamber 15 and the temperature sensor 21 to rapidly increase. When the temperature sensor 21 exceeds a set temperature (for example, 60 ° C.), the inverter power supply circuit is controlled to stop the motor 7 or the motor 7 By accelerating for a certain period of time, the return of the retained lubricating oil in the pipe can be promoted.

Further, in FIG. 2, the lubricating oil collected in the discharge space oil sump 22 is cooled while passing through the oil return pipe 25 and the oil cooling device 28,
After the pressure is reduced by the external expansion device 26, an appropriate amount is discharged from the tip of the nozzle 23a toward the temperature sensor 21 arranged in the motor chamber 15 in the low temperature atmosphere in the obliquely lower position, and finally the oil sump at the bottom is released.
It is collected in 17 and then circulated in the same manner as in the example of FIG.

If there is a shortage of lubricating oil in the oil sump 17 or the discharge space oil sump 22, the temperature of the temperature sensor 21 will rise rapidly in the same procedure as in the example of FIG. 1, and the temperature sensor 21 will reach the set temperature (for example, 60 ° C). When the value exceeds the limit, the external expansion device 26 operates to cut off the passage, and the inverter power supply circuit is controlled to accelerate the return of the lubricating oil in the pipe by speeding up the motor 7 for a certain period of time. After the external return passage 27 is shut off, when the temperature sensor 21 recovers below the set temperature, the external return passage 27 is opened again, and the lubricating oil in the discharge space oil sump 22 is returned to the motor chamber 15 again in an appropriate amount.

It should be noted that in the above embodiment, when the temperature sensor 21 exceeds the set temperature, the external expansion device 31b is shut off, but it is also possible to perform control to further narrow down the passage without completely shutting off.

In the embodiment shown in FIGS. 1 and 2, the motor chamber 15 has a low pressure side and the discharge space oil sump 22 is provided inside the compressor. However, as long as the atmospheric temperature can be kept relatively low, The motor chamber 15 may be arranged on the intermediate pressure side, and the same operation as in the above embodiment can be obtained by substituting the discharge space oil reservoir 22 with an oil separator of a simple structure provided on the discharge side outside the compressor.

As described above, according to the above embodiment, the refrigerant is separated from the compressed refrigerant gas on the high pressure side of the refrigeration cycle (the oil separator provided in the discharge piping system outside the compressor or the discharge space 13 inside the compressor), and the bottom of the oil separator is separated. The lubricating oil stored in the oil reservoir 22 or the discharge space is arranged in the suction refrigerant gas passage by disposing the drive shaft 8 provided with the eccentric oil hole 18 for centrifugal pump oil supply and the motor 10 driven by the inverter power supply. An oil return passage 31 including an ultrafine passage 19 (or external expansion device 26) returning to the low-pressure side motor chamber 15 and a nozzle 23 (or 23a).
(Or 31a) is provided, and the opening end of the oil return passage 31 (or 31a) to the motor chamber 15 is arranged in the motor chamber 15 to control the flow rate of the oil return passage 31a and control the compressor rotation speed (inverter power supply drive). By arranging the temperature sensor 21 closely related to the function of stopping the motor 10 or increasing the rotation speed of the motor 10 by, for example, the compressor low speed operation is continued for a long time in a long pipe refrigeration cycle, and the refrigerant flow velocity is If the lubricating oil stays in the piping that is slow and runs short of the lubricating oil inside the compressor, or when the defrosting operation is in progress during the heating / refrigerating cycle, the fin temperature of the condenser is extremely low and the condenser capacity is large. If the non-evaporated refrigerant liquid containing lubricating oil containing insufficient lubricating oil stays in the accumulator on the low pressure side of the refrigeration cycle and the lubricating oil inside the compressor becomes insufficient, the oil sump on the high pressure side (discharging space) (Refer to the oil reservoir 22) and the viscosity is high and the pressure is appropriately reduced in the ultra-fine passage 19 and the external expansion device 26 and returns to the motor chamber 15 by an appropriate amount. A large amount of gas flows into the motor chamber 15 through 23a) to raise the temperature sensor 21 to the set temperature and it is very difficult to change the mixing ratio of the lubricating oil and the discharge refrigerant gas in the oil sump (the discharge space oil sump 23, etc.). Detection can be realized with a simple configuration.This configuration has a fast response speed, so the operation of the compressor is controlled to stop the compressor when the lubricating oil is insufficient or to increase the refrigerant flow rate by increasing the compressor rotation speed. The lubricating oil retained in the piping system can be returned to the compressor to improve the durability of the compressor and also improve the efficiency of the heat exchanger to improve the efficiency of the cooling and heating device.

Further, in the above embodiment, the interior of the compressor formed by the closed cases 1 and 2 is partitioned by the frame 3 into the motor chamber 15 (low pressure side) and the discharge space 13 (high pressure side), and the bottom of the discharge space oil sump 22 is divided. By providing the high pressure side open end of the oil return passage 31 (or 31a), an oil separator device for separating the lubricating oil from the discharged refrigerant gas can be easily built in the compressor to control the lubricating oil temperature. Controls the oil return passage 31a (lubrication) in the presence or absence of lubricating oil in the oil reservoir on the high-pressure side or the change in the lubricating oil mixing ratio in the discharged refrigerant gas at a high detection speed because the oil is discharged toward the sensor 22. Compressor by improving the durability of the compressor based on early securing of lubricating oil by advancing the timing of flow rate reduction) or controlling (stopping or increasing) the rotational speed of the compressor, and by sealing the minute gap in the compression chamber with lubricating oil. The efficiency can be improved and the motor By reducing the inflow of the discharged refrigerant gas into the chamber 15, it is possible to suppress the deterioration of the refrigeration cycle efficiency.

Further, in the above embodiment, the opening end (the tip of the nozzle 23, 23a) of the oil return passage 31 (or 31a) to the motor chamber 15 on the low pressure side is provided above the temperature sensor 21, so that the motor chamber from the high pressure side is The lubricating oil or the discharged refrigerant gas returning to 15 can surely hit the temperature sensor 21 regardless of its viscosity and the magnitude of the differential pressure between the high pressure side and the low pressure side, thereby enhancing the operational reliability of the temperature sensor 21.

Further, in the above embodiment, the temperature sensor 21 also serves as a temperature protector for detecting the overcurrent of the motor 10, so that there is no need to provide a new temperature sensor and the cost is low enough to improve the conventional temperature sensor when the lubricating oil is insufficient. It is possible to provide the discharge oil return control device required for improving the compressor durability and the compression efficiency of the compressor. The discharge refrigerant gas starts flowing into the motor chamber 15 through the oil return passage 31 (or 31a) and the ambient temperature of the motor chamber 15 Suddenly rises, the motor efficiency decreases and the motor input current increases, and the temperature sensor 21 is heated by both the motor input current and the discharged refrigerant gas, and the oil return passage 31 (or 31
It is possible to improve the responsiveness of the temperature sensor 21 to the detection of the inflow of the discharged refrigerant gas by, for example, shortening the time period during which the temperature is raised to the set temperature for controlling the operation of the compressor (a) or the compressor.

EFFECTS OF THE INVENTION As described above, the present invention is an extremely fine oil return for returning the lubricating oil separated from the compressed gas on the high pressure side to the low pressure side where the drive source of the compressor and the lubricating oil supply device are arranged or the intermediate pressure side of the low temperature atmosphere. A passage is provided, and the opening end of the oil return passage to the low pressure side or the intermediate pressure side of the low temperature atmosphere is arranged at the low pressure side or the intermediate pressure side of the low temperature atmosphere to control the flow rate of the oil return passage or the rotation speed of the compressor. By providing the temperature sensor linked to the lubricating oil recovery control function in close proximity to it, when the lubricating oil runs low on the high-pressure side, the viscosity is high until then, and the pressure is appropriately reduced in the ultra-fine oil return passage, and the compressor is compressed. An appropriate amount of compressed gas with low viscosity flows in through the oil return passage instead of the lubricating oil that returns to the low pressure side or the intermediate pressure side where the ambient temperature is not high, where the drive source etc. is high, and the temperature sensor rises to the set temperature. It is possible to realize the inflow discrimination between the lubricating oil and the compressed gas, which is extremely difficult to keep warm, with a simple structure, and because the structure directly touches the temperature sensor with the lubricating oil and the compressed gas, the response speed is fast, and the low pressure side and the intermediate pressure side It is possible to prevent the inflow of compressed gas as quickly as possible to prevent a decrease in compressor efficiency, and to control the operation of the compressor to stop the compressor in the condition of insufficient lubricating oil or reduce the durability of the compressor by deceleration. It is possible to improve, and by operating the control device to secure the lubricating oil and recovering the lubricating oil in the compressor, part of the lubricating oil flows into the compression chamber together with the intake gas, and the minute gap in the compression chamber is sealed with the lubricating oil and compressed. The compression efficiency can be improved by preventing leakage of gas.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a scroll gas compressor according to a first embodiment of the present invention, and FIG. 2 is a vertical sectional view of a scroll gas compressor according to a second embodiment of the present invention, FIGS. FIG. 3 is a cross-sectional view of scroll gas compressors having different conventional oil return passages. 1,2 ... closed case, 3 ... frame, 7 ... motor,
8 ... Drive shaft, 10 ... Orbiting scroll, 11 ... Fixed scroll, 13 ... Discharge space, 15 ... Motor chamber, 17 ... Oil sump, 19 ... Extra fine passage, 21 ... Temperature sensor, 22 ... … Discharge space oil sump, 23,23a …… Nozzle, 26 …… External expansion device, 3
1,31a …… Oil return passage.

Claims (4)

[Claims] 1. A low-pressure side in which an electric motor and a scroll compressor driven by the electric motor are provided in a closed container, and lubricating oil separated from compressed gas on the high-pressure side is provided with a drive source of the compressor and a lubricating oil supply device. Alternatively, a fine oil return passage for returning to the intermediate pressure side of the low temperature atmosphere is provided, and the opening end of the oil return passage to the low pressure side or the intermediate pressure side is controlled by the flow rate of the oil return passage, the rotation speed control of the compressor, or the lubrication. A scroll gas compressor installed close to and facing a temperature sensor linked to oil recovery control. 2. A scroll gas according to claim 1, wherein the inside of the hermetic case of the compressor is partitioned into a low pressure side and a high pressure side, and a high pressure side opening end of an oil return passage is provided at an oil sump bottom portion of the high pressure side. Compressor. 3. The scroll gas compressor according to claim 1, wherein the opening end of the oil return passage to the low pressure side is provided above the temperature sensor. 4. The scroll gas compressor according to claim 1 or 2, wherein the drive source is an electric motor, and the temperature sensor also serves as a temperature protector for protecting the electric motor.