JPS63106392A - Scroll type gas compressor - Google Patents

Abstract

PURPOSE:To prevent the reduction of the compressor efficiency by forming the downstream side of an oil return passage for returning the lubricating oil separated from the compressed gas on the high pressure side to a driving chamber under a low pressure, into a nozzle form directed towards a temperature sensor. CONSTITUTION:In a sealed case 1, 2, a compression mechanism part consisting of a swirl scroll 10, fixed scroll 11, etc. is installed, and a discharge space 13 is formed in the upper part side, and a driving chamber 15 in the suction pressure environment into which an electric motor 7 is housed is formed on the lower side. Between the discharge space 13 and the driving chamber 15, an oil return hole 19 for returning the lubricating oil which is separated from the discharged gas in the discharge space 13 into the driving chamber 15 is formed, and a nozzle-shaped oil discharge pipe 23 directed towards a temperature sensor 21 is installed on the downstream side. When a large amount of discharge gas is discharged at a high speed from the oil discharge pipe 23, the temperature of the temperature sensor 21 part rises, and the shortage of the lubricating oil can be certainly detected, and the reduction of the compressor efficiency can be coped with.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a scroll gas compressor.

Conventional technology A scroll compressor with low vibration and noise characteristics has a suction chamber on the outer periphery and a discharge port in the center of a thin spiral, which allows compressed fluid to flow in one direction and has high suction volumetric efficiency. is well known.

However, especially when compressing gas, the dimensional accuracy of the thinly wound part must be extremely high in order to reduce the leakage gap in the compression part, but the cost of scroll compressors increases due to the complexity of the part shape and dimensional variations. There were problems in that the performance was high and the performance varied greatly.

Therefore, in order to solve this kind of problem,
The structure shown in FIG. 4, as known from Japanese Patent Application No. 093, and the structure shown in FIG. Based on the idea that the lubricating oil is caused to flow into the compression chamber together with the suction gas, and after being compressed and discharged, the lubricating oil is separated from the compressed gas and returned to the space leading to the lubricating oil reservoir. After the lubricating oil is introduced into the oil separation tank 118, the lubricating oil is separated in the oil separation tank 118 and transferred to the capillary tube 117b.
It was configured so that the air was returned to the closed container 112 at an intermediate pressure between the discharge pressure and the suction pressure.

Further, in FIG. 5, the lubricating oil separated from the compressed gas in the cap 219 is returned to the space 280 forming the suction passage through the holes 222 to 284.

Problems to be Solved by the Invention However, in the configuration in which compressed gas and lubricating oil are returned to the closed container 112 in an intermediate pressure state through the capillary tube 117b without distinction, as shown in Fig. gS4 above, the lubricating oil is insufficient and the compressed gas is When returning to the closed container 112, the passage resistance is low because the viscosity is low, and a large amount is stored in the closed container@? 1112, significantly reducing compression efficiency, and oil separation tank 1.
18 with the function of returning only the lubricating oil, the cost is high and the oil separation tank 118 itself becomes large and requires a lot of space to hang. On the other hand, if the compressor continues to operate without returning the lubricating oil, there will be a shortage of lubricating oil. This caused a variety of complex problems, including a decrease in compression efficiency and damage to the compressor.

Furthermore, when there is little lubricating oil in a configuration without an oil return control mechanism as shown in FIG. There was a problem in that it caused a significant drop in performance.

Therefore, the present invention has developed an inexpensive, highly efficient, and durable scroll in which the tip of the oil return passage that opens on the downstream side toward the temperature sensor that distinguishes between the lubricating oil return state and the compressed gas return state is shaped into a nozzle. The present invention provides a gas compressor.

Means for Solving the Problems In order to solve the above problems, the scroll gas compressor of the present invention has a drive source for the compressor and a lubricating oil supply device arranged to supply the lubricating oil separated from the compressed gas on the high pressure side. An oil return passage with a narrow passage for returning the oil to the drive chamber on the low pressure side or intermediate pressure side in a low-temperature atmosphere is provided, and a temperature sensor related to the flow rate control of the oil return passage, the compressor rotation speed control function, or the lubricating oil recovery control function is installed. The oil return passage is provided in the drive chamber, and the downstream opening end of the oil return passage is arranged to face the temperature sensor, and the downstream opening end of the oil return passage is shaped like a nozzle.

According to the above structure, the lubricating oil is compressed and discharged together with the suction gas, and the lubricating oil separated from the compressed gas or the compressed gas containing the lubricating oil is continuously delivered from the nozzle tip of the oil return passage to the drive chamber in a low temperature atmosphere. The high temperature compressed gas or lubricating oil is released toward the main part of the temperature sensor located in the drive chamber, and the released high temperature compressed gas or lubricating oil reliably collides with the temperature sensor without being affected by the diffusion of gas in the drive chamber. Unfortunately, when lubricating oil passes through the oil return passage, the flow rate is low and the temperature rise in the temperature sensor is low, allowing the compressor to operate continuously, but for some reason compressed gas passes through the oil return passage. In this case, since the viscosity is low and the passage resistance is low, the amount of compressed gas flowing in increases significantly, causing the temperature sensor to rise to an abnormal temperature, causing the oil return passage to be shut off, the oil return passage to be throttled, or the compressor to be stopped. Alternatively, we can provide a highly reliable, highly efficient, and durable scroll gas compressor that prevents a decrease in compression efficiency and damage to sliding parts due to lack of lubricating oil by controlling lubricating oil by increasing or decreasing the rotational speed, etc. It is something.

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

FIG. 1 shows a vertical cross-sectional view of a scroll gas compressor according to a first embodiment of the present invention, FIG. 2 shows a vertical cross-sectional view of a scroll gas compressor according to a second embodiment of the present invention, and FIG. The figure shows a longitudinal section of a scroll gas compressor and an explanatory diagram of an oil return passage control system in a third embodiment of the present invention.

In FIG. 1, 1 and 2 are iron sealed cases, 3 is a 7-frame iron frame, and its outer surface is welded and sealed together with the sealed case 1.2 by a single weld bead 6.
2 is partitioned into an upper discharge space 1a and a lower drive chamber 15 (low pressure side).

The eccentric hole 9 at the upper end of the drive shaft 8 is supported by the frame 3 and is rotatably driven by a motor 7 whose operation is controlled by an inverter power supply (not shown).
is fitted by engaging the rotation prevention part, and a fixed flow/l'11 having a discharge boat 30 that engages therewith is bolted to the frame 3.

A discharge space 13 formed by the sealed case 1, the frame 3, and the fixed flow/l/11 communicates with an external piping system through a discharge pipe 14 provided in the sealed case 1, and is The formed low-pressure side drive chamber 15 communicates with an external piping system through a suction pipe 16 provided in the sealed case 2, and an oil sump 17 is provided at the bottom of the drive chamber 15, which connects the eccentric hole 9 and the oil sump. The lower end of the drive shaft 8 has an eccentric oil hole 18 that communicates with the oil sump 17 .

A temperature sensor 21 is attached to the upper coil end 20 of the motor 7, which also serves to prevent overcurrent of the motor 7.
3 and the W moving chamber 15 is an oil discharge pipe 2 which opens at the bottom of the discharge space oil sump 22 and is provided in the frame 3 and has a return hole 19 for returning the discharged oil, and a nozzle-shaped oil discharge pipe 2 with an extremely narrow passage connected thereto.
The oil discharge pipes communicate with each other through an oil return passage 31 formed from the temperature sensor 21, and the tips of the oil discharge pipes are provided above the temperature sensor 21 in close proximity to each other.

A glass terminal 24 for electrically connecting a power supply device outside the compressor and the motor 7 is provided in the sealed case 2 near the temperature sensor 21.

Further, in FIG. 2, an oil return passage 31a consisting of a return hole 19a provided in the frame 3a and an extremely thin oil discharge hole 32 that is straight and has an appropriate length is located between the discharge space oil sump 22 and the drive chamber 15. are communicating.

In addition, Figure @3 shows an oil return pipe 25 that opens at the bottom of the discharge space oil sump 22 and penetrates the sealed case 1 between the discharge space oil sump 22 and the drive chamber 15, and an oil return pipe 25 that is provided outside the compressor and that is connected to the drive chamber 15. It communicates with an external throttle device 26 that operates in conjunction with the sensor 21 and an oil return passage 31b that passes through a nozzle-shaped oil discharge pipe 23a that extends through the sealed case 2 and extends to the upper part near the temperature sensor 210. , an oil cooling device 28 is provided in the middle.

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

In FIG. 1, when the drive shaft 8 is rotationally driven by the motor 7, the rotating flow /l/10 makes a rotating movement, and after the refrigerant gas flows into the drive chamber 15 through the suction pipe 16, the lubricant contained in the refrigerant gas A part of the oil is separated and confined in a compression chamber formed between the orbiting scroll 10 and the fixed flow A/11, compressed by the orbiting movement of the orbiting flow A/10, and discharged from the discharge port 30. space 13
A part of the lubricating oil contained in the discharged refrigerant gas is separated from the discharged refrigerant gas due to its own weight and collected in the discharge space oil sump 22, which has a return hole 19 and an extremely thin nozzle shape for pressure reduction. The lubricating oil is discharged in a straight line through the oil discharge pipe 23 toward the temperature sensor 21 located in the drive chamber 15 in the low-temperature atmosphere directly below, and some of the scattered lubricating oil also splashes on the terminals of the glass terminal 24 and finally Specifically, the oil is collected in an oil reservoir 17 at the bottom, and after being supplied to bearing sliding surfaces and the like by the centrifugal pump action of the eccentric oil hole 18 of the drive shaft 8, it is compressed and discharged together with the sucked refrigerant gas.

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

In this circulation cycle of refrigerant gas and lubricating oil, lubricating oil with an appropriate viscosity has the function of lubricating the sliding parts and sealing small gaps in the compression chamber, and contributes to stable operation of the compressor.
If the lubricating oil becomes unstable in the oil sump 17 or the discharge space oil sump 22 (
For example, if the piping in the refrigeration cycle is very long and the refrigerant speed in the piping is slow, such as when the compressor is running at low speed, lubricating oil will stay in the piping and not return to the compressor, resulting in a lubricant shortage.) A large amount of high-temperature refrigerant gas with extremely low viscosity and low passage resistance is injected from the discharge space 13 toward the temperature sensor 21 from the nozzle-shaped oil discharge pipe 23 with an extremely narrow passage, and the temperature sensor 21 rises rapidly. When the ambient temperature in the motor room 15 also rises and the temperature sensor 21 exceeds the set temperature (for example, 60°C), the inverter power supply circuit is controlled to stop the motor 7 or stop the motor 7.
By increasing the speed for a certain period of time, the return of the lubricating oil remaining in the pipe is promoted.

2, the lubricating oil in the discharge space oil sump 22 is depressurized through the extremely thin oil discharge hole 32 and is injected toward the temperature sensor 21, after which it is circulated in the same manner as in the example shown in FIG.

Further, in FIG. 3, 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, and after being depressurized by the external throttling device 26, is led to the oil discharge pipe 23a. The oil is injected toward the temperature sensor 2.1 located directly below the outlet of the oil discharge pipe 23a, and finally reaches the oil sump 1 at the bottom.
7, and thereafter circulated in the same manner as in the example of FIG.

In the event that there is a shortage of lubricating oil in the oil reservoir 17 or the discharge space oil reservoir 22, the temperature of the temperature sensor 21 will rise rapidly by following the same procedure as in the example shown in FIG.
When the temperature exceeds 0° C., the external throttle device 26 operates to cut off the passage, and the inverter power supply circuit is controlled to increase the speed of the motor 7 for a certain period of time to promote the return of the lubricating oil remaining in the pipe. After the external return passage 27 is shut off, when the temperature sensor 21 returns to the set temperature or lower, the external return passage 27 is opened again and the lubricating oil in the discharge space oil reservoir 22 is returned to the drive chamber 15 again.

In the above embodiment, when the temperature sensor 21 exceeds the set temperature, the external throttle device 31b is shut off, but the external throttle device 31b may not be shut off completely, but the passage may be further narrowed.

In addition, in the embodiments shown in grJ1, @2, and 3, the drive chamber 15 is on the low pressure side and the discharge space oil sump 22 is provided inside the compressor, but the ambient temperature can be kept relatively low. The drive chamber 15 may be configured to be on the intermediate pressure side, and the same effect as in the above embodiment can be obtained even if the discharge space oil reservoir 22 is replaced with an oil separator of a simple structure provided on the discharge side outside the compressor. It will be done.

As described above, according to the above embodiment, the oil 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 idle pipe 13 inside the compressor), and the oil is separated from the compressed refrigerant gas at the bottom of the oil separator. A motor 10 driven by an inverter power supply or a drive shaft 8 driven by the motor 10 and having an eccentric hole 18 for refueling a centrifugal pump is arranged to transfer the lubricating oil stored in the oil sump 22 and the discharge space into suction refrigerant gas. An oil return passage 19 consisting of an oil discharge pipe 23 and a return hole 19 (or an oil discharge hole 32 having an extremely narrow passage and a recess hole 19a, or an oil return passage 31b consisting of an external throttle device 26, an oil discharge pipe 23a, etc.
) to control the flow rate of the oil return passage 31b (opening/closing the passage or adjusting the opening using the external throttling device 26), stopping or restarting the compressor, or controlling lubricating oil recovery (by increasing the rotational speed of the motor 10 for a certain period of time). Temperature sensor 21 related to the function of increasing the flow rate of refrigerant circulating through the refrigeration cycle and returning the lubricating oil stagnant in the piping system to the compressor together with the refrigerant.
is provided in the drive chamber 15, and the oil return passage 31 ("!
The downstream opening end of the oil return passage 31 (or 31a or 31b) is arranged to face the temperature sensor 21, and the downstream opening end of the oil return passage 31 (or 31a or 31b) is shaped like a nozzle with a small diameter. If the lubricating oil inside the compressor becomes insufficient due to stagnation,
Or, during defrosting operation during heating/refrigeration cycle operation, the fin temperature of the condenser is extremely low, the condensing capacity is large, and the heat absorption of the evaporator is insufficient, causing unevaporated refrigerant liquid containing lubricating oil to enter the low-pressure side of the refrigeration cycle. When the lubricating oil inside the compressor becomes insufficient due to accumulation in the accumulator, high viscosity oil is transferred from the oil reservoir on the high pressure side (discharge space oil reservoir 22, etc.) to the oil discharge pipe 23 in the extremely narrow passage (or equipment 26, etc.)
The pressure is moderately reduced in the drive chamber 15 from the small diameter oil discharge opening end.
Instead of the lubricating oil, which is injected in appropriate amounts and at increased speed, a large amount of discharged refrigerant gas with low viscosity is injected at high speed toward the temperature sensor 21 and is affected by gas diffusion by the high-speed rotating body in the drive chamber 15. Temperature sensor 2
The lubricating oil and the discharged refrigerant gas in extremely difficult oil sumps (such as the oil sump 23 in the discharge space) collide with the temperature sensor 21 to intensively raise the temperature to the set temperature. Temperature-sensitive responsiveness can be quickly and reliably realized with a simple configuration for detecting changes in the mixing ratio.Based on this detection, compressor operation can be controlled to stop the compressor early in the event of a lack of lubricating oil, or to reduce the compressor rotation speed. By increasing the refrigerant flow rate, the lubricating oil accumulated in the piping system is returned to the compressor, increasing the durability of the compressor and increasing the efficiency of the heat exchanger. Since the speed of the compressed gas is high, the discharged refrigerant gas reliably collides with the temperature sensor 21 without being affected by gas diffusion within the drive chamber 15.
By narrowing the space of the compressor 5 and increasing the rotational speed of the drive shaft 8, the compressor can be made faster and smaller.

Further, in the above embodiment, the oil return passage 31 (or 31at
or 31b) by making the small-diameter nozzle-shaped part at the downstream opening end into a tubular oil discharge pipe 23 (or 23a),
Since the downstream opening end of the oil return passage can be extended to the vicinity of the temperature sensor 21, the lubricating oil for oil return and the discharged refrigerant gas are hardly affected by gas diffusion by the rotating body in the drive chamber 15, and the temperature There are no restrictions on the placement location or orientation of the sensor 21, making it possible to save space in the drive chamber 15, and the oil return function can reduce the influence of the size of the drive chamber 15 and the rotation speed of the drive device. .

Furthermore, in the above embodiment, by making the small-diameter nozzle shape part the oil discharge hole 32 that also serves as an extremely narrow passage, an extremely inexpensive oil return passage can be formed, which contributes to improving the durability of the compressor and the efficiency of the heat exchanger. can do.

Effects of the Invention As described above, the present invention provides an ultra-fine pipe that returns lubricating oil separated from compressed gas on the high-pressure side to the drive chamber on the low-pressure side or intermediate-pressure side in a low-temperature atmosphere where the drive source of the compressor and lubricating oil supply device are arranged. An oil return passage having a passage is provided, a temperature sensor related to the flow control function of the oil return passage, the compressor rotational speed control function, or the lubricating oil recovery control function is provided in the drive chamber, and the downstream opening end of the oil return passage is provided. Placed opposite the temperature sensor,
By making the downstream opening end of the oil return passage into a small-diameter nozzle shape, when the lubricating oil becomes insufficient on the high pressure side, the viscous oil is moderately reduced in the oil return passage and the compressor drive source is removed. In place of the lubricating oil that returns in appropriate amounts to the drive chamber on the low-pressure side or intermediate-pressure side where the ambient temperature is not high, compressed gas with low viscosity is accelerated at the narrow diameter part of the downstream opening end of the oil return passage. A large amount flows in and the temperature sensing part of the temperature sensor intensively raises the temperature to the set temperature, so it is very difficult to distinguish between lubricating oil and compressed gas flowing into the drive chamber.It has a simple configuration and has a fast temperature sensing response. A fluid return status detection device is now available, which quickly restricts the inflow of compressed gas to the low-pressure side and intermediate-pressure side to prevent a decrease in compressor efficiency, and also controls compressor operation to detect lubricant shortage conditions. The durability of the compressor can be improved by stopping or decelerating the compressor, and the lubricating oil inside the compressor can be restored by operating the control device to secure the lubricating oil.
- By doing so, a part of the lubricating oil flows into the compression chamber together with the suction gas, sealing the small gap in the compression chamber with the lubricating oil, reducing the leakage of compressed gas from the gap, and quickly recovering the compression efficiency. The speed of the compressed gas that is accelerated and injected by the nozzle shape is fast, so it is not affected by gas diffusion caused by high-speed rotating bodies in the drive chamber.The pressure gas reliably reaches the temperature sensor, so the drive chamber is not idle. By narrowing the compressor and increasing the rotational speed of the main shaft of the compressor, the compressor can be made faster and more compact.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a scroll gas compressor according to a first embodiment of the present invention, FIG. 2 is a vertical cross-sectional view of a scroll gas compressor according to a second embodiment of the present invention, and FIG. 2 shows a longitudinal section of a scroll gas compressor according to a third embodiment of the present invention, and FIGS. 4 and 5 show sectional views of a scroll/L/gas compressor equipped with different conventional oil return passages, respectively. . 1.2... Sealed case, 3... Frame, 7... Motor, 8... Drive shaft, 1
0...Orbiting scroll, 11...Fixed scroll, 13...Discharge space, 15...
...Drive chamber, 17...Oil sump, 21...
Temperature sensor, 22...Discharge idle oil sump, 23,
23a... Oil discharge pipe, 26... External throttle device, 31, 31a. 31b...Oil return passage. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 4
Figure 5

Claims (3)

[Claims] (1) Equipped with an electric motor and a scroll compressor driven by the electric motor in a closed container, lubricating oil separated from compressed gas on the high pressure side is supplied to the low pressure side or low temperature side where the drive source of the compressor and lubricating oil supply device are arranged. An oil return passage having an extremely narrow passage returning the oil to the drive chamber on the intermediate pressure side of the atmosphere is provided, and a temperature sensor related to flow rate control of the oil return passage, compressor rotation speed control, or lubricant recovery control is provided in the drive chamber. A scroll gas compressor, wherein the downstream opening end of the oil return passage is arranged opposite to the temperature sensor, and the downstream opening end of the oil return passage is shaped like a small diameter nozzle. (2) The scroll gas compressor according to claim 1, wherein the small-diameter nozzle-shaped portion is a tubular passage. (3) The scroll gas compressor according to claim 1 or 2, wherein the small-diameter nozzle-shaped portion also serves as an extremely narrow passage.