JPH06103038B2 - 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 eddy coil extremely high in order to reduce the leakage gap of the compression part, but the cost of the scroll compressor is high due to the complexity of the part shape and the dimensional variation. There was a problem that there were large variations in performance.

Therefore, in order to solve this kind of problem, as shown in 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. 5 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. 4, 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. 5, the space in which the lubricating oil separated from the compressed gas in the cap 219 forms the suction passage through the holes 222 to 284.
It was configured to be returned to 280.

Problems to be Solved by the Invention However, in the configuration in which the compressed gas and the lubricating oil as shown in FIG. 4 are returned to the closed container 112 in the intermediate pressure state through the capillary tube 117b without any distinction, the lubricating oil is insufficient and the compressed gas is compressed. When it returns to the closed container 112, the viscosity is low, so the passage resistance is small, and a large amount of it flows into the closed container 112 to significantly reduce the compression efficiency, and the function of returning only the lubricating oil to the oil separation tank 118 is provided. High cost when equipped with oil separation tank
118 itself became large and required a lot of installation space, but when the compressor operation was continued without returning the lubricating oil, there were many complex problems such as lack of lubricating oil, resulting in deterioration of compression efficiency and damage to the compressor. .

Further, when the oil return control mechanism as shown in FIG. 5 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 the compression efficiency. There was a problem of slowing down.

Therefore, in the present invention, the tip of the oil return passage opening downstream toward the temperature sensor for discriminating the lubricating oil return state and the compressed gas return state is formed into a nozzle shape, and the scroll is inexpensive, highly efficient, and has excellent durability. A gas compressor is provided.

Means for Solving the Problems In order to solve the above problems, the scroll gas compressor of the present invention is configured such that the lubricating oil separated from the compressed gas on the high pressure side has a low pressure in which a drive source of the compressor and a lubricating oil supply device are arranged. Side or the intermediate pressure side drive chamber of the low temperature atmosphere is provided with an oil return passage having an extra-fine passage, and the 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 provided in the drive chamber. 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 has a nozzle shape.

Effect of the Invention With the above configuration, the lubricating oil is compressed and discharged together with the intake gas, and the lubricating oil or the compressed gas containing the lubricating oil is continuously discharged from the nozzle tip of the oil return passage to the driving chamber in the low temperature atmosphere. The hot compressed gas or lubricating oil that is discharged toward the main part of the temperature sensor placed will surely collide with the temperature sensor without being affected by the diffusion of gas in the driving chamber to heat the temperature sensor. However, when the lubricating oil passes through the oil return passage, the flow rate is low and the temperature sensor temperature rise is low, and the compressor continues to operate.However, if the compressed gas passes through the oil return passage for some reason, Since the viscosity is low and the passage resistance is small, the inflow amount of compressed gas increases remarkably and the temperature sensor rises abnormally to shut off the oil return passage or throttle the oil return passage. Also, it is highly reliable and highly reliable in preventing compression efficiency drop and sliding part damage due to lack of lubricating oil by establishing lubricating oil securing control by stopping the compressor or increasing / decreasing the rotation speed. It is possible to provide a scroll gas compressor.

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, FIG. 2 shows a vertical 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-made hermetically sealed cases, 3 is an iron frame, and its outer contact surface is welded and hermetically sealed together with the hermetically sealed cases 1 and 2 by a single welding bead 6, and the inside of the hermetically sealed cases 1 and 2 is discharged upward It is partitioned into a space 13 and a lower drive 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 drive chamber 15 which is connected to the external piping system through the frame 14 and is formed by the frame 3 and the closed case 2 is connected to the external pipe system through the suction pipe 16 provided in the closed case 2 and is connected to the drive chamber. An oil sump 17 is provided at the bottom of 15, and the lower end of the drive shaft 8 having an eccentric oil hole 18 communicating the eccentric hole 9 and the oil sump 17 is buried in the oil sump 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 drive chamber 15 is opened at the bottom of the discharge space oil sump 22 and provided in the frame 3. Is communicated with an oil return passage 31 constituted by a return hole 19 for returning the discharged oil and an oil discharge pipe 23 having a nozzle shape of an ultrafine passage connected to the return hole 19, and the tip of the oil discharge pipe is close to the upper portion of the temperature sensor 21. It is provided facing 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 temperature sensor 21.

Further, FIG. 2 shows that an oil return passage 31a consisting of a return hole 19a provided in the frame 3a and a fine oil release hole 32 which is straight and has an appropriate length is provided between the discharge space oil reservoir 22 and the drive chamber 15. Are in communication.

Further, FIG. 3 shows an oil return pipe 25 penetrating the closed case 1 that opens between the discharge space oil sump 22 and the drive chamber 15 at the bottom of the discharge space oil sump 22, and is provided outside the compressor. An oil return passage 31b passing through an external expansion device 26 that operates in association with the sensor 21 and a nozzle-shaped oil discharge pipe 23a that penetrates through the closed case 2 and extends to an upper portion near the temperature sensor 21. However, an oil cooling device 28 is provided on the way.

The operation of the scroll gas 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 drive chamber 15 through the suction pipe 16, one of the lubricating oil contained in the refrigerant gas is discharged. The parts are separated and enclosed in a compression chamber formed between the orbiting scroll 10 and the fixed scroll 11,
Compressed with the orbiting movement of the orbiting scroll 10 and discharged from the discharge port 30 to the discharge space 13, a part of the lubricating oil contained in the discharge refrigerant gas is separated from the discharge refrigerant gas by its own weight, etc. Collected in reservoir 22, return hole 19
And a part of the lubricating oil that is linearly discharged toward the temperature sensor 21 arranged in the driving chamber 15 in the low temperature atmosphere directly below through the oil discharge pipe 23 having an ultrafine nozzle shape for depressurization. Is also sprayed to the terminals of the glass terminal 24 and finally collected in the oil sump 17 at the bottom, and is fed to the bearing sliding surface and the like by the centrifugal pump action of the eccentric oil hole 18 of the drive shaft 8. Along with this, it is compressed and discharged.

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.

Such a lubricating oil having an appropriate viscosity in the circulation cycle of the refrigerant gas and the lubricating oil has a lubricating function for the sliding portion and a sealing function for a minute gap in the compression chamber, which contributes to stable operation of the compressor.
If the lubricating oil is not fixed in the oil sump 17 or the discharge space oil sump 22 (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 a low speed) Is accumulated in the compressor and does not return to the inside of the compressor, causing a shortage of lubricating oil), and the high-temperature refrigerant gas with extremely low viscosity and low passage resistance from the discharge space 13 is discharged from the oil discharge pipe 23 in the shape of a nozzle in an ultrafine passage. A large amount of fuel is injected toward the sensor 21, the temperature sensor 21 rapidly rises, and the ambient temperature of the motor chamber 15 also rises, so that the temperature sensor 21 sets a preset temperature (for example,
When the temperature exceeds 60 ° C., the inverter power supply circuit is controlled to stop the motor 7 or accelerate the motor 7 for a certain period of time to accelerate the feedback of the retained lubricating oil in the pipe.

Further, in FIG. 2, the lubricating oil in the discharge space oil sump 22 is decompressed by the extremely fine oil discharge hole 32 and injected toward the temperature sensor 21, and thereafter circulates in the same manner as in the example of FIG.

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, decompressed by the external expansion device 26, and then guided to the oil discharge pipe 23a. The oil is injected toward the temperature sensor 21 arranged just below the outlet of the oil discharge pipe 23a, finally collected in the oil sump 17 at the bottom, and thereafter 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 blocked, 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 drive chamber 15 again.

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, 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 is kept relatively low. If possible, the drive chamber 15 may be on the intermediate pressure side.Also, the discharge space oil sump 22 may be replaced by an oil separator of a simple structure provided on the discharge side outside the compressor, and the same effect as in the above embodiment can be obtained. can get.

As described above, according to the above embodiment, 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) separates the compressed refrigerant gas from the bottom of the oil separator and An eccentric oil hole for supplying centrifugal oil to the motor 10 driven by an inverter power supply and the lubricating oil accumulated in the discharge space oil sump 22 and the like, which is driven by the motor 10.
An oil return passage 19 (oil return pipe 19 having an oil discharge pipe 23 and a return hole 19 having an ultrafine passage for arranging the drive shaft 8 having 18 to return to the low pressure side drive chamber 15 forming a part of the intake refrigerant gas passage) Alternatively, an oil return passage 31a including an oil discharge hole 32 having a fine passage and a return hole 19a or an oil return passage 31b including an external expansion device 26 and an oil discharge pipe 23a) is provided to control the flow rate of the oil return passage 31b ( In the piping system, the flow rate of the refrigerant circulating in the refrigeration cycle is increased by stopping or restarting the compressor or controlling the lubricating oil recovery by increasing the rotation speed of the motor 10 for a certain period of time by opening or closing the passage or adjusting the opening degree by the external expansion device 26. The temperature sensor 21 related to the function of returning the lubricating oil staying in the compressor together with the refrigerant into the compressor is provided in the drive chamber 15, and the oil return passage 31 (or 31a) is provided.
Alternatively, by arranging the downstream opening end of 31b) so as to face the temperature sensor 21, and by making the downstream opening end of the oil return passage 31 (or 31a or 31b) into a nozzle-like thin diameter, for example, long piping When the low-speed operation of the compressor continues in the refrigeration cycle for a long time and the lubricating oil stays in the pipe where the refrigerant flow velocity is slow and the lubricating oil in the compressor is insufficient, or during defrosting operation during the heating / refrigeration cycle operation. In addition, the fin temperature of the condenser is extremely low, the condensation capacity is large, the heat absorption of the evaporator is insufficient, and the unevaporated refrigerant liquid containing lubricating oil stays in the accumulator on the low pressure side of the refrigeration cycle and the lubricating oil inside the compressor If a shortage occurs, the oil sump on the high pressure side (discharging space oil sump 22
To a lubricating oil that is highly viscous and is moderately decompressed by an oil discharge pipe 23 (or an external expansion device 26, etc.) in an ultrafine passage, and is accelerated and injected from the thin oil discharge opening end into the drive chamber 15 by an appropriate amount. Instead, a large amount of the low-viscosity discharge refrigerant gas is injected at high speed toward the temperature sensor 21, and the discharge refrigerant gas is reliably affected by the temperature sensor 21 without being affected by gas diffusion by the high-speed rotating body in the drive chamber 15. Detects changes in the mixing ratio of lubricating oil and discharge refrigerant gas in a very difficult oil sump (such as the discharge space oil sump 23) by colliding with the temperature sensor 21 and raising the temperature of the temperature sensor to the set temperature intensively The temperature sensing response can be realized quickly and surely with a simple configuration, and based on this detection, the operation of the compressor can be controlled to stop the compressor early when the lubricating oil is insufficient, or to increase the rotational speed of the compressor to control the refrigerant flow rate. Oil that has increased and accumulated 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,
Since the velocity of the compressed gas injected from the small-diameter nozzle shape portion is high, the discharge refrigerant gas reliably collides with the temperature sensor 21 without being affected by gas diffusion in the drive chamber 15, so that the space of the drive chamber 15 is narrowed. In addition, the rotation speed of the drive shaft 8 is increased and the compressor can be downsized at high speed.

Further, in the above embodiment, the oil return passage 31 (or 31a or 3
The temperature sensor 2 is configured by using the tubular oil discharge pipe 23 (or 23a) as the small-diameter nozzle-shaped portion at the downstream opening end of 1b).
Since the opening end on the downstream side of the oil return passage can be extended to the vicinity of 1, the lubricating oil for returning oil and the discharged refrigerant gas are hardly affected by gas diffusion by the rotating body in the drive chamber 15, and the temperature sensor 21 Since there is little restriction on the arrangement location and arrangement posture of the drive chamber 15, the space inside the drive chamber 15 can be further saved, 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.

Further, in the above embodiment, by forming the small-diameter nozzle-shaped portion as the oil discharge hole 32 that also serves as an ultrafine passage, an extremely inexpensive oil return passage can be formed, which contributes to the improvement of the durability of the compressor and the efficiency of the heat exchanger. can do.

As described above, according to the present invention, the lubricating oil separated from the compressed gas on the high pressure side is returned to the driving chamber on the low pressure side or the intermediate pressure side of the low temperature atmosphere in which the driving source of the compressor and the lubricating oil supply device are arranged. An oil return passage having a passage is provided, and a temperature sensor related to the flow rate control of the oil return passage, the control function of the compressor rotation speed or the lubricating oil recovery control function is provided in the drive chamber, and the downstream opening end of the oil return passage is heated. Place it facing the sensor,
When the downstream opening end of the oil return passage has a small nozzle shape, if the lubricating oil runs short on the high pressure side, the viscosity will be high until then and the oil return passage will be moderately depressurized to drive the compressor drive source. Compressed gas with low viscosity is accelerated in the small diameter section at the downstream opening end of the oil return passage instead of lubricating oil that returns an appropriate amount to the low pressure side or intermediate pressure side drive chamber where the ambient temperature is not high. A large amount of inflow and temperature sensor intensively detects the temperature sensitive part.The temperature can be rapidly raised to the set temperature, so it is very difficult to distinguish between lubricating oil and compressed gas in the driving chamber. The return state detection device becomes possible, and it is possible to prevent the compressed gas from flowing into the low pressure side and the intermediate pressure side quickly and prevent the deterioration of the compressor efficiency. Compressor by stopping or decelerating The durability can be improved, and the control device for securing the lubricating oil is operated to recover the lubricating oil in the compressor, so that part of the lubricating oil flows into the compression chamber together with the suction gas, and the minute gap in the compression chamber is sealed with the lubricating oil. As a result, the leakage of compressed gas can be reduced and the compression efficiency can be recovered quickly. Furthermore, the velocity of the compressed gas that is accelerated by the small-diameter nozzle shape is high, so that gas diffusion by the high-speed rotating body in the drive chamber is possible. Since the compressed gas reliably reaches the temperature sensor, the space of the driving chamber can be narrowed, the rotation speed of the main shaft of the compressor can be increased, and the compressor can be downsized at high speed.

[Brief description of drawings]

1 is a vertical sectional view of a scroll gas compressor according to a first embodiment of the present invention, FIG. 2 is a vertical sectional view of a scroll gas compressor according to a second embodiment of the present invention, and FIG. FIG. 4 is a vertical sectional view of a scroll gas compressor according to the third embodiment of the present invention, and FIGS. 4 and 5 are sectional views 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 ... Drive chamber, 17 ... Oil sump,
21 …… Temperature sensor, 22 …… Discharge space oil sump, 23,23a ……
Oil discharge pipe, 26 ... external expansion device, 31, 31a, 31b ... oil return passage.

Claims (3)

[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, an oil return passage having an ultrafine passage for returning to the drive chamber on the intermediate pressure side of the low temperature atmosphere is provided, and the temperature sensor involved in the flow rate control of the oil return passage, the rotation speed control of the compressor, or the recovery control of the lubricating oil is driven. Set up in the room,
A scroll gas compressor in which 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 has a small-diameter nozzle shape. 2. The scroll gas compressor according to claim 1, wherein the narrow nozzle shape portion is a tubular passage. 3. The scroll gas compressor according to claim 1, wherein the small-diameter nozzle shape portion also serves as an ultrafine passage.