JPH07218007A - Protecting apparatus for compressor - Google Patents

Abstract

PURPOSE:To prevent seizing of a compressor of a refrigerating cycle due to flow-out of lubricant. CONSTITUTION:A low-pressure tube 10 coupled to a suction inlet of a compressor 1 of a refrigerating cycle 11 is connected to a high-pressure tube 2 coupled to a discharge port via a bypass conduit 12 having a check valve 13. When a refrigerant pressure of the tube 10 side becomes larger than hat of the tube 2 side at the time of stopping the compressor 1, the refrigerant of the tube 10 side is preferentially fed to the tube 2 side through the conduit 12 and the valve 13 so that the refrigerant does not flow to the compressor 1, thereby preventing flow-out of lubricant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compressor protection device in a refrigeration cycle provided in an air conditioner or the like.

[0002]

2. Description of the Related Art A refrigeration cycle provided in an air conditioner, such as a vehicle air conditioner, includes a compressor, a condenser, a receiver,
The expansion valve and the evaporator are connected in sequence through a pipe, and a lubricating oil that circulates with a refrigerant to lubricate the compressor is enclosed in the refrigeration cycle.

[0003]

By the way, in this type of refrigeration cycle, when the operation of the compressor (operation of the refrigeration cycle) is stopped and the condenser is cooled by the outside air or the evaporator is warmed by solar radiation, There is a temperature difference between the two so that the temperature of the evaporator becomes higher than the temperature of the condenser, which causes a pressure difference between the two so that the pressure of the refrigerant in the evaporator becomes greater than the pressure of the refrigerant in the condenser. Will occur. In this case, since the operation of the compressor is stopped, the circulation of the lubricating oil is lost, and therefore, as described above,
When a pressure difference occurs between the refrigerant of the evaporator and the condenser, only the gas refrigerant vaporized by the evaporator flows into the suction port of the compressor.

In principle, when the operation of the compressor is stopped, the refrigerant flow path should be blocked by a valve, a vane or the like between the suction port and the discharge port of the compressor. Has a slight gap between the internal components due to the manufacturing precision and the assembly precision, so that a leakage flow passage with a relatively large flow passage resistance from the suction port to the discharge port is formed. The gaseous refrigerant from the evaporator flows to the condenser side through this leak flow path. Therefore, the lubricating oil in the compressor flows out to the condenser side together with the gas refrigerant flowing through the leakage flow path, and when the operation of the compressor is restarted next, the lubricating oil in the compressor becomes insufficient and seizure occurs. was there.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a compressor protection device which does not cause seizure due to lack of lubricating oil in the compressor when the compressor is restarted. To provide.

[0006]

A compressor protection device of the present invention is provided with a bypass passage for connecting a low-pressure side and a high-pressure side of a refrigeration cycle equipped with a compressor for compressing a refrigerant circulating with lubricating oil, The bypass passage is characterized by being provided with a check valve that allows the refrigerant to flow from the low pressure side to the high pressure side (claim 1).

In this case, the low pressure side may be set to a low pressure pipe connected to the suction port of the compressor, and the high pressure side may be set to a high pressure pipe connected to the discharge port of the compressor (claim 2). Further, it is more preferable to dispose the bypass passage and the check valve inside the compressor (claim 3).

Further, the low pressure side can be set to a pipe between the expansion valve and the evaporator of the refrigerant cycle, and the high pressure side can be set to a high pressure pipe connected to the discharge port of the compressor (claim). (4) Alternatively, the low pressure side may be set as a low pressure pipe connected to the suction port of the compressor, and the high pressure side may be set as a pipe between the condenser and the expansion valve of the refrigeration cycle ( Claim 5).

The low pressure side may be set to a low pressure pipe connected to the suction port of the compressor, and the high pressure side may be set to a pipe between the receiver and the expansion valve of the refrigeration cycle. (6) Alternatively, the low pressure side may be set to a pipe between the expansion valve and the evaporator of the refrigeration cycle, and the high pressure side may be set to a pipe between the condenser and the receiver of the refrigeration cycle ( 8. The method according to claim 7, wherein the low pressure side is set to a pipe between the expansion valve and the evaporator of the refrigeration cycle, and the high pressure side is set to a pipe between the receiver and the expansion valve of the refrigeration cycle. Good (Claim 8).

[0010]

According to the compressor protection device of the first aspect, when the pressure of the refrigerant on the low pressure side of the refrigeration cycle becomes higher than the pressure of the refrigerant on the high pressure side when the operation of the compressor is stopped, the pressure is increased. Due to the difference, the check valve in the bypass passage is opened, so that the low-pressure side refrigerant flows to the high-pressure side through the bypass passage, and the low-pressure side refrigerant is prevented from flowing into the compressor as much as possible. It

According to the compressor protection device of the second aspect, when the refrigerant pressure on the low pressure side, which is the low pressure side, becomes larger than the refrigerant pressure on the high pressure side, which is the high pressure side, when the operation of the compressor is stopped. Due to the pressure difference, the non-return valve of the bypass passage is opened, and therefore the refrigerant on the low pressure pipe side passes through the bypass passage and takes precedence over the leakage flow passage with a large flow resistance of the compressor. Therefore, the refrigerant on the low-pressure pipe side is prevented from flowing into the compressor as much as possible. In this case, by disposing the bypass passage and the check valve inside the compressor, a compact structure can be achieved (claim 3).

According to the compressor protection device of the fourth aspect, the refrigerant pressure on the pipe side between the expansion valve on the low pressure side and the evaporator when the operation of the compressor is stopped is the refrigerant pressure on the high pressure pipe side which is the high pressure side. When it becomes larger than the above, the pressure difference causes the refrigerant on the piping side between the expansion valve and the evaporator to bypass the evaporator and the compressor via the bypass passage and almost flow to the high pressure piping side. Therefore, the low-pressure side refrigerant is prevented from flowing into the compressor as much as possible.

According to the compressor protection device of the fifth aspect, the refrigerant pressure on the low pressure side, which is the low pressure side, when the operation of the compressor is stopped, is the refrigerant pressure on the pipe side between the condenser, which is the high pressure side, and the expansion valve. When it becomes larger than the above, the refrigerant on the low pressure side bypasses the compressor and the condenser via the bypass passage and almost flows to the side of the pipe between the condenser and the expansion valve, and thus the low pressure side. The refrigerant is prevented from flowing into the compressor as much as possible.

According to the compressor protection device of the sixth aspect, the refrigerant pressure on the low-pressure pipe side, which is the low-pressure side when the compressor is stopped, is the refrigerant pressure on the pipe side between the receiver, which is the high-pressure side, and the expansion valve. When it becomes larger than the above, the refrigerant on the low pressure pipe side bypasses the compressor, the condenser and the receiver via the bypass passage and almost flows to the pipe side between the receiver and the expansion valve. The refrigerant on the low pressure side is prevented from flowing into the compressor as much as possible.

According to the compressor protection device of the seventh aspect, when the operation of the compressor is stopped, the pressure of the refrigerant on the pipe side between the expansion valve, which is the low pressure side, and the evaporator is the high pressure side. When the refrigerant pressure on the pipe side between them becomes larger than that on the pipe side, the refrigerant on the pipe side between the expansion valve and the evaporator bypasses the evaporator, the compressor and the condenser through the bypass passage to form the condenser and the receiver. Almost all the gas flows in the space between the pipes, so that the refrigerant on the low pressure side is prevented from flowing into the compressor as much as possible.

According to the compressor protection device of the eighth aspect, when the operation of the compressor is stopped, the refrigerant pressure on the pipe side between the expansion valve on the low pressure side and the evaporator is on the high pressure side. When the refrigerant pressure on the piping side between the two becomes higher than the refrigerant pressure on the piping side, the refrigerant on the piping side between the expansion valve and the evaporator bypasses the evaporator, compressor, condenser and receiver via the bypass path and expands with the receiver. Almost all of the refrigerant flows to the pipe side between the valve and the valve, so that the refrigerant on the low pressure side is prevented from flowing into the compressor as much as possible.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment in which the present invention is applied to a vehicle air conditioner will be described below with reference to FIGS. First, in FIG. 1, a discharge port of a through-vane type (crank type or swash plate type) compressor 1 is connected to an inlet of a condenser 3 via a high-pressure pipe 2, and an outlet of the condenser 3 is Receiver 5 via pipe 4
The outlet of the receiver 5 is connected to the inlet of the evaporator 9 via the pipe 6, the expansion valve 7 and the pipe 8, and the outlet of the evaporator 9 is connected to the low pressure pipe 1.
The refrigeration cycle 11 is configured by being connected to the suction port of the compressor 1 via 0.

On the other hand, in the refrigeration cycle 11, the low-pressure side low-pressure pipe 10 is connected to the high-pressure side high-pressure pipe 2 by a bypass line 12 which is a bypass line, and the bypass line 12 is provided with a check valve 13. It is arranged together with the compression coil spring 14 as a biasing means. The check valve 13 always closes the bypass line 12 by the urging force of the compression coil spring 14, but the refrigerant pressure in the low pressure pipe 10 is higher than the refrigerant pressure in the high pressure pipe 2 by a predetermined value or more. When it becomes large, the bypass line 12 is opened (opened)
The refrigerant on the low-pressure pipe 10 side is allowed to flow to the high-pressure pipe 2 side.
5 are configured.

Next, the operation of this embodiment will be described.
Now, when the compressor 1 is driven by the vehicle engine and starts to operate, the refrigerant is compressed into a high-pressure gaseous refrigerant,
This is supplied to the condenser 3 via the high-pressure pipe 2, and the high-pressure gas refrigerant is condensed by the condenser 3 to become a high-pressure liquid refrigerant. The liquid refrigerant from the condenser 3 is
It is supplied to the expansion valve 7 through the pipe 4, the receiver 5, and the pipe 6, and is expanded there to become a low-pressure refrigerant, which is the pipe 8.
And is supplied to the evaporator 9 via Then, the refrigerant supplied to the evaporator 9 is evaporated here to become a low-pressure gas refrigerant, which is returned to the compressor 1 via the low-pressure pipe 10.

In this case, since the refrigerant pressure in the high-pressure pipe 2 is higher than the refrigerant pressure in the low-pressure pipe 10 during the operation of the compressor 1, the check valve 13 of the bypass pipe 12 has the check valve 13 thereof. Is held in a closed state, so that the refrigerant on the high-pressure pipe 2 side does not flow to the low-pressure pipe 10 side via the bypass line 12. Lubricating oil is enclosed in the refrigeration cycle 11, and during operation of the compressor 1, the lubricating oil circulates together with the refrigerant to lubricate the compressor 1. The condenser 3 is cooled by the contact with the outside air, and the cool air of the evaporator 9 is sent to the passenger compartment.

When the operation of the compressor 1 is stopped, the cooling operation of the refrigeration cycle 11 as described above is also stopped. In this case, when the condenser 3 is cooled by the outside air or the evaporator 9 is warmed by the solar radiation, a temperature difference is generated between the condenser 3 and the evaporator 9 so that the temperature of the evaporator 9 becomes higher than the temperature of the condenser 3. There is a pressure difference between the two so that the pressure of the refrigerant becomes greater than the pressure of the refrigerant in the condenser 3. In this case, since the operation of the compressor 1 is stopped, the circulation of lubricating oil is lost.

Thus, the evaporator 9 side, that is, the low pressure pipe 1
When the refrigerant pressure on the 0 side becomes larger than the refrigerant pressure on the condenser 3 side, that is, the high-pressure pipe 2 side by a predetermined value or more, the check valve 13 opens due to the pressure difference due to the biasing force of the compression coil spring 14. become. When the operation of the compressor 1 is stopped, a leakage flow path from the suction port to the discharge port is formed in the compressor 1 as in the conventional case. Since it is larger than the flow path resistance of the line 12, the refrigerant on the low pressure pipe 10 side flows preferentially through the bypass line 12 to the high pressure pipe 2 side, so that the refrigerant on the low pressure pipe 10 side is compressed. It is prevented as much as possible from flowing into the leak passage in the machine 1.

As described above, according to this embodiment, the check valve 13 is provided between the low pressure pipe 10 and the high pressure pipe 2 of the refrigerant cycle 11.
Is provided, and when the refrigerant pressure on the low-pressure pipe 10 side becomes larger than the refrigerant pressure on the high-pressure pipe 2 side when the compressor 1 is stopped, the refrigerant on the low-pressure pipe 10 side is bypassed. The high-pressure pipe 2 is preferentially flowed through the passage 12. Therefore, the refrigerant on the low-pressure pipe 10 side is prevented from flowing into the compressor 1 as much as possible, and unlike the conventional case, the refrigerant inflow from the suction port into the compressor 1 and the refrigerant outflow from the discharge port are almost eliminated. The lubricating oil in the compressor 1 will not flow out to the condenser 3 side, and the compressor 1 will not be burned when the restart of the compressor 1 is started.

Moreover, a bypass line 12 having a check valve 13 and a compression coil spring 14 is provided between the low pressure pipe 10 connected to the suction port of the compressor 1 and the high pressure pipe 2 connected to the discharge port. Since it is a simple structure, the object can be achieved with a simple structure.

FIG. 3 shows a second embodiment of the present invention. The difference from the first embodiment is that a storage chamber 1a is formed in the upper part of the compressor 1 and a low pressure is stored in the storage chamber 1a. Piping 1
0, a part of the high-pressure pipe 2, a bypass pipe line 12 for connecting them, a check valve 13, and a compression coil spring 14.
The holding device 15 consisting of is arranged and housed.

Therefore, according to this second embodiment, the first
It is possible to obtain the same effects as those of the above embodiment, and in particular, since the protection device 15 is incorporated in the compressor 1, the configuration becomes more compact.

In each of the above embodiments, the protection device 15 is provided between the low pressure pipe 10 and the high pressure pipe 2.
For example, even with the configurations shown in FIGS. 4 to 8, substantially the same effects as in the first embodiment can be obtained.

That is, in the third embodiment of the present invention shown in FIG. 4, the pipe 8 between the expansion valve 7 on the low pressure side and the evaporator 9 is provided.
A protection device 15 is provided between the high pressure side 2 and the high pressure side.
When the refrigerant pressure on the pipe 8 side becomes higher than the refrigerant pressure on the high-pressure pipe 2 side when the compressor 1 is stopped, the refrigerant on the pipe 8 side bypasses the evaporator 9 and the compressor 1 to the high-pressure pipe 2 side. It was made to flow.

Further, in the fourth embodiment of the present invention shown in FIG. 5, the low-pressure side low-pressure pipe 10 and the high-pressure side condenser 3 are provided.
The protection device 15 is provided between the receiver 1 and the pipe, for example, the pipe 4, and the low-pressure pipe 1 is provided when the compressor 1 is stopped.
When the refrigerant pressure on the 0 side becomes larger than the refrigerant pressure on the pipe 4 side, the refrigerant on the low pressure pipe 10 side bypasses the compressor 1 and the condenser 3 and flows to the pipe 4 side.

In the fifth embodiment of the present invention shown in FIG. 6, a protective device 15 is provided between the low pressure side low pressure pipe 10 and the high pressure side receiver 5 and the pipe 6 between the expansion valve 7 and the compressor 1
When the refrigerant pressure on the low-pressure pipe 10 side becomes larger than the refrigerant pressure on the pipe 6 side at the time of the operation stop of, the refrigerant on the low-pressure pipe 10 side bypasses the compressor 1, the condenser 3 and the receiver 5, and the pipe 6 side. It was made to flow to.

In the sixth embodiment of the present invention shown in FIG. 7, a protective device 15 is provided between the pipe 8 between the expansion valve 7 on the low pressure side and the evaporator 9 and the pipe 3 between the condenser 3 and the receiver 5 on the high pressure side. When the refrigerant pressure on the pipe 8 side becomes larger than the refrigerant pressure on the pipe 4 side when the compressor 1 is stopped, the refrigerant on the pipe 8 side is cooled by the evaporator 9 and the compressor 1.
Also, the condenser 3 is bypassed to flow to the side of the pipe 4.

Then, in the seventh embodiment of the present invention shown in FIG. 8, between the pipe 8 between the low pressure side expansion valve 7 and the evaporator 9 and the high pressure side receiver 5 and the pipe 6 between the expansion valve 7. When the protection device 15 is provided and the refrigerant pressure on the pipe 8 side becomes larger than the refrigerant pressure on the pipe 6 side when the compressor 1 is stopped, the refrigerant on the pipe 8 side is evaporated, the compressor 1, the condenser 3 And the pipe 5 bypassing the receiver 5
It was made to flow to the side.

In addition, the present invention is not limited to the above-mentioned respective embodiments, and can be applied not only to an air conditioner for a vehicle but also to an air conditioner in general. It is needless to say that the present invention can be appropriately modified and carried out within a range not departing from the gist such as being applicable to compressors of a refrigeration cycle which are reversed.

[0034]

As described above, the compressor protection device of the present invention has a low pressure when the refrigerant pressure on the low pressure side of the refrigeration cycle becomes higher than the refrigerant pressure on the high pressure side when the operation of the compressor is stopped. Since the refrigerant on the side of the compressor is allowed to flow preferentially to the high pressure side through the bypass passage and the check valve to prevent the refrigerant from flowing into the compressor as much as possible, the compressor burns when restarting the operation of the compressor. It does not cause ties.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a refrigeration cycle showing a first embodiment of the present invention.

[Figure 2] Enlarged view of the main part

FIG. 3 is a view corresponding to FIG. 2 showing a second embodiment of the present invention.

FIG. 4 is a diagram corresponding to FIG. 1 showing a third embodiment of the present invention.

FIG. 5 is a view corresponding to FIG. 1 showing a fourth embodiment of the present invention.

FIG. 6 is a view corresponding to FIG. 1 showing a fifth embodiment of the present invention.

FIG. 7 is a diagram corresponding to FIG. 1 showing a sixth embodiment of the present invention.

FIG. 8 is a view corresponding to FIG. 1 showing a seventh embodiment of the present invention.

[Explanation of symbols]

In the drawings, 1 is a compressor, 2 is high pressure piping (high pressure side), 3 is a condenser, 4 is piping (high pressure side), 6 is piping (high pressure side),
7 is an expansion valve, 8 is piping (low pressure side), 9 is an evaporator,
10 is a low pressure pipe (low pressure side), 11 is a refrigeration cycle, 12
Is a bypass line (bypass line), 13 is a check valve, and 15 is a protective device.

Claims (8)

[Claims] 1. A bypass passage that connects a low pressure side and a high pressure side of a refrigeration cycle including a compressor that compresses a refrigerant that circulates together with lubricating oil is provided, and a refrigerant passage from the low pressure side to the high pressure side is provided in the bypass passage. A protective device for a compressor, which is provided with a check valve for allowing circulation. 2. The low-pressure side is set to a low-pressure pipe connected to the suction port of the compressor, and the high-pressure side is set to a high-pressure pipe connected to the discharge port of the compressor. The protection device for a compressor according to claim 1. 3. The compressor protection device according to claim 2, wherein the bypass passage and the check valve are arranged inside the compressor. 4. The low pressure side is set to a pipe between the expansion valve and the evaporator of the refrigeration cycle, and the high pressure side is set to a high pressure pipe connected to a discharge port of the compressor. The compressor protection device according to claim 1. 5. The low-pressure side is set to a low-pressure pipe connected to the suction port of the compressor, and the high-pressure side is set to a pipe between the condenser and the expansion valve of the refrigeration cycle. The compressor protection device according to claim 1. 6. The low-pressure side is set to a low-pressure pipe connected to the suction port of the compressor, and the high-pressure side is set to a pipe between the receiver and the expansion valve of the refrigeration cycle. The compressor protection device according to claim 1. 7. The low pressure side is set to a pipe between the expansion valve and the evaporator of the refrigeration cycle, and the high pressure side is set to a pipe between the condenser and the receiver of the refrigeration cycle. The compressor protection device according to claim 1. 8. The low pressure side is set to a pipe between the expansion valve and the evaporator of the refrigeration cycle, and the high pressure side is set to a pipe between the receiver and the expansion valve of the refrigeration cycle. The compressor protection device according to claim 1, wherein the protection device is a compressor.