JP2004230974A - Compressor for vehicle air conditioning - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent seizure of a compressor by outflow of lubrication oil without reducing operation efficiency. <P>SOLUTION: A low pressure passage 15 and a high pressure passage 17 of the compressor 1 are communicated via a by-pass passage 18, and the by-pass passage 18 is provided with a trigger valve 20. The trigger valve 20 is closed by pressure difference of a cooling medium at an operation time. Thus, the cooling medium in poured from a low pressure port 12 is led into a housing 10 without passing through the by-pass passage 18, compressed by a piston, and flows out from a high pressure port 13. When the compressor is stopped, the trigger valve 20 is opened by energizing force of a spring 23. Thus, the cooling medium in poured from the low pressure port 12 passes through the by-pass passage 18 and flows out from the high pressure port 13. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a vehicle air conditioning compressor suitable for use in a vehicle air conditioner.
[0002]
[Prior art]
If the vehicle is left for a long period of time, refrigerant gas moves from the high-temperature evaporator side to the low-temperature compressor side due to the temperature difference between the vehicle interior and the vehicle exterior. As a result, the refrigerant gas enters the compressor, and the refrigerant cooled and liquefied in the low-temperature compressor is pushed out to the condenser side. At that time, the lubricating oil of the compressor dissolves in the liquefied refrigerant and flows out of the compressor together with the liquefied refrigerant. If this phenomenon is repeated, the lubricating oil of the compressor may run short.
[0003]
In order to prevent such a shortage of the lubricating oil of the compressor, there has been known a compressor in which an elastically deformable valve body is provided in an inflow passage of the refrigerant gas to the compressor (for example, see Patent Document 1). According to this, when the compressor is stopped, the passage is closed by the valve body to prevent the refrigerant gas from entering the compressor. When the inflow pressure of the refrigerant gas rises due to the operation of the compressor, the valve element is elastically deformed by the inflow pressure to open the inflow passage and guide the refrigerant gas into the compressor.
[0004]
[Patent Document 1]
JP 2000-352376 A
[Problems to be solved by the invention]
In the above, since the valve element is elastically deformed by the inflow pressure of the refrigerant gas to open the inflow passage, the passage resistance increases, and the operating efficiency of the compressor decreases. If the elasticity of the valve body is reduced to suppress the increase in the passage resistance and the valve body is easily elastically deformed, it may not be possible to reliably prevent the refrigerant gas from entering the compressor when the vehicle is left unattended.
[0006]
The present invention provides an air-conditioning compressor that can prevent a shortage of compressor lubricating oil without lowering operating efficiency.
[0007]
[Means for Solving the Problems]
The vehicle air-conditioning compressor according to the present invention includes a compressor housing, a refrigerant compression mechanism built in the compressor housing, a refrigerant path that compresses the refrigerant flowing from the low-pressure port by the refrigerant compression mechanism and guides the refrigerant to the high-pressure port, and at least a refrigerant path. It is characterized by including a bypass passage that partially bypasses the refrigerant flowing from the low-pressure port to the high-pressure port, and a valve mechanism that closes the bypass passage when the compressor operates and opens the bypass passage when the compressor stops.
[0008]
【The invention's effect】
In the present invention, a bypass passage is provided for bypassing at least a part of the refrigerant passage to guide the refrigerant from the low-pressure port to the high-pressure port. The bypass passage is closed when the compressor is operating, and the bypass passage is opened when the compressor is stopped. did. As a result, it is possible to prevent the outflow of the compressor lubricating oil when the compressor is stopped and to prevent the passage resistance from increasing when the compressor is operating, and to suppress the shortage of the compressor lubricating oil without lowering the operation efficiency.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS.
FIG. 1 is an external side view showing a vehicle air conditioning compressor 1 according to an embodiment of the present invention, and FIG. 2 is a diagram showing a flow of an air conditioning refrigerant. As shown in FIG. 2, the refrigerant pumped by the compressor 1 sequentially passes through the condenser 2, the expansion valve 3, and the evaporator 4 which form a known refrigeration cycle together with the compressor 1 and returns to the compressor 1. That is, the refrigerant compressed by the compressor 1 exchanges heat with the outside air in the condenser 2 to be radiated, and then expanded by the expansion valve 3. Then, the evaporator 4 exchanges heat with the air in the air-conditioning duct communicating with the vehicle interior, absorbs heat, and cools the air in the air-conditioning duct.
[0010]
The compressor 1 is a swash plate type variable displacement compressor. The compressor 1 drives a piston in the compressor 1 by a driving force of an engine input through a pulley 11 to compress a refrigerant flowing from a low pressure port 12 and a high pressure port 13 (FIG. 3). See). Further, the inclination of the swash plate in the compressor 1 is changed in accordance with the suction pressure of the refrigerant to change the refrigerant discharge amount. The compressor 1 has a housing 10 integrally or separately cast and formed, and the housing 10 is provided with a passage for the following refrigerant.
[0011]
3A is a cross-sectional view taken along the line III-III of FIG. 1, and FIG. 3B is a cross-sectional view taken along the line bb of FIG. 3A. FIG. 3A corresponds to the vertical direction when the vehicle is mounted. The low pressure port 12 and the high pressure port 13 are provided close to each other on the upper side of the housing 10. The low-pressure port 12 and the high-pressure port 13 are provided with a low-pressure passage 15 and a high-pressure passage 17, respectively, and ends 15 a and 17 a of the passages 15 and 17 are located at an upper portion of the housing 10. A low-pressure chamber 14 is provided on the outer circumferential side in the housing 10 (see FIG. 5), and the low-pressure passage 15 and the low-pressure chamber 14 communicate with each other in a cross section (not shown). A high-pressure chamber 16 is provided on the inner diameter side of the low-pressure chamber 14 via a partition 10a, and the high-pressure passage 17 and the high-pressure chamber 16 communicate with each other. The low-pressure chamber 14 and the high-pressure chamber 16 communicate with each other via a piston chamber in the housing 10. When the piston is driven, the refrigerant in the low-pressure chamber 14 is guided to the piston chamber to have a high pressure, and is sent to the high-pressure chamber 16.
[0012]
As a characteristic configuration of the present embodiment, the low-pressure passage 15 and the high-pressure passage 17 communicate with each other via a bypass passage 18 as shown in FIG. 3B, and a trigger valve 20 (check valve) is provided in the bypass passage 18. ing. Note that the bypass passage 18 is formed in the housing 10.
[0013]
FIG. 4 is an enlarged view of the IV section in FIG. 3B showing the configuration of the trigger valve 20. The trigger valve 20 has a substantially cylindrical bush 21, a ball 22 and a spring 23 disposed in the bush 21. The bush 21 includes a large-diameter portion 21a on the high-pressure port 13 side, a small-diameter portion 21b on the low-pressure port 12 side, and an intermediate tapered portion 21c. The bush 21 is inserted into the bypass passage 18 from the high-pressure port 13 side. 18a. The ball 22 has a larger diameter than the small-diameter portion 21b and a smaller diameter than the large-diameter portion 21a, and can move between the tapered portion 21c and the convex portion 21d provided on the inner wall surface of the bush after the ball is inserted. One end of the spring 23 is fixed to the low pressure port side end 21 e of the bush 21, and the other end is in contact with the ball 22.
[0014]
When the pressure difference between the low pressure port 12 and the high pressure port 13 is greater than the urging force of the spring 23, the ball 22 is pushed toward the low pressure port 12 as shown in FIG. Abut As a result, the trigger valve 20 is closed, and the flow of the refrigerant in the bypass passage 18 is blocked. On the other hand, when the pressure difference between the low pressure port 12 and the high pressure port 13 is equal to or less than the urging force of the spring 23, the ball 22 is pushed toward the high pressure port 13 by the urging force of the spring 23 as shown in FIG. The ball 22 is separated from the tapered portion 21c. Thereby, the trigger valve 20 is opened, and the flow of the refrigerant in the bypass passage 18 is allowed. As described above, the trigger valve 20 is opened and closed according to the pressure difference of the refrigerant and the urging force of the spring 23. In the present embodiment, the trigger valve 20 closes when the compressor 1 operates and opens when the compressor 1 stops. The spring 23 is set as described above.
[0015]
Here, the burn-in phenomenon of the compressor 1 will be described with reference to the schematic diagram of FIG. FIG. 6 corresponds to a cross-sectional view taken along the line VI-VI in FIG. When the compressor 1 is stopped, the low-pressure chamber 14 and the high-pressure chamber 16 in the housing 10 are filled with the liquid refrigerant as shown in FIG. If the vehicle is left for a long time in this state, the temperature of the vehicle interior rises due to solar radiation, and the pressure of the gas refrigerant in the evaporator 4 increases. Thereby, the gas refrigerant of the evaporator 4 moves to the low temperature side, that is, the compressor 1 side, and the liquid refrigerant in the housing 10 is pushed as shown in FIG. 6B, and the liquid refrigerant flows out of the high pressure port 13 to the condenser 2 side. . At this time, the lubricating oil of the compressor 1 dissolved in the liquid refrigerant is taken out of the housing 10.
[0016]
When the liquid level H of the refrigerant in the housing 10 gradually decreases due to the outflow of the liquid refrigerant, and the liquid level H becomes lower than the ports 12 and 13 as shown in FIG. When the pressure is lower than the ends 15a and 17a, the low-pressure port 12 and the high-pressure port 13 communicate with each other without passing through the liquid refrigerant. Thus, the gas refrigerant from the evaporator 4 passes through the low-pressure chamber 14 and the high-pressure chamber 16 in the housing 10 and flows toward the condenser 2 without taking out the liquid refrigerant. When such a phenomenon is repeated, the lubricating oil of the compressor 1 gradually decreases, and the compressor 1 may be seized due to poor lubrication.
[0017]
On the other hand, in the present embodiment, when the compressor 1 is stopped, the trigger valve 20 is opened by the urging force of the spring 23 (FIG. 5B). Therefore, as shown in FIG. 7, the gas refrigerant from the evaporator 4 flows into the high-pressure passage 17 via the bypass passage 18. That is, the gas refrigerant flows from the low-pressure port 12 to the high-pressure port 13, bypassing the low-pressure chamber 14 and the high-pressure chamber 16 in the housing 10. This prevents the liquid refrigerant from being taken out of the compressor 1 and prevents a decrease in lubricating oil when the vehicle is left unattended.
[0018]
When the compressor 1 operates, a pressure difference is generated between the low-pressure passage 15 and the high-pressure passage 17, and the pressure difference closes the trigger valve 20 against the urging force of the spring 23 (FIG. 5A). Thereby, the refrigerant from the low pressure port 12 is all guided into the housing 10 without bypassing the low pressure chamber 14 and the high pressure chamber 16 and is compressed by the piston. In this case, since the valve 20 is closed by the pressure difference of the refrigerant, leakage of the refrigerant from the low-pressure passage 14 to the high-pressure passage 16 can be prevented. In addition, since an opening / closing valve is not provided in the refrigerant circulation passage (for example, the low-pressure passage 15 and the high-pressure passage 17) during the operation of the compressor, the passage resistance does not increase and the operating efficiency of the compressor 1 can be prevented from lowering.
[0019]
According to the present embodiment described above, the following operational effects can be obtained.
(1) A bypass passage 18 that connects the low-pressure passage 15 and the high-pressure passage 17 is provided, a trigger valve 20 is provided in the bypass passage 18, and the valve 20 is opened by a spring 23 when the compressor is stopped. The valve 20 was closed. As a result, it is possible to prevent the outflow of the lubricating oil of the compressor when the compressor is stopped and to prevent the passage resistance from increasing when the compressor is operating, and to prevent the shortage of the lubricating oil of the compressor without lowering the operating efficiency.
(2) Since the bypass passage 18 and the trigger valve 20 are provided in the housing 10, there is no need to separately construct the bypass passage 18 with a pipe or the like, so that the cost can be reduced.
(3) Since the ball 22 that moves in the direction to close the bypass passage 18 due to the pressure difference of the refrigerant and the spring 23 that applies a biasing force to the ball 22 in the direction to open the passage 18 are provided in the bush 21, the trigger is provided. The valve 20 can be easily configured, and the sealing performance of the valve 20 is improved.
(4) Since the passage ends 15a and 17a are provided in the upper portion of the housing 10, the outflow of the liquid refrigerant when the compressor is stopped can be prevented to the maximum.
[0020]
In the above embodiment, the bypass passage 18 is formed so as to bypass all of the low-pressure chamber 14, the high-pressure chamber 16 and the piston chamber in the housing 10. However, the bypass passage 18 is formed so as to bypass a part of the refrigerant path. It may be formed. For example, the bypass passage 19 may be formed from the upper part of the low-pressure chamber 14 to the high-pressure passage 17 or from the low-pressure passage 15 to the upper part of the high-pressure chamber 16. Although the bypass passage 18 is formed in the housing 10, the invention is not limited thereto, and the passages 15 and 17 may be communicated with each other by a pipe or the like.
[0021]
Although the trigger valve 23 is formed by the ball 22 and the spring 23, another valve mechanism may be adopted as long as the bypass passage 18 is closed when the compressor operates and the bypass passage 18 is opened when the compressor stops. Although the housing 10 is formed by casting, the method of manufacturing the housing 10 is not limited to this. The shapes of the ports 12, 13 and the passage 15 are variously changed depending on the type of the compressor 1, and are not limited to those described above. That is, the above embodiment is applied to the swash plate type variable displacement compressor 1, but may be a fixed displacement type. Further, the present invention can be similarly applied to a compressor having another refrigerant compression mechanism (for example, a scroll type or a vane type). Therefore, the route of the refrigerant circulating in the compressor 1 is not limited to the above-described one, and the present invention is not limited to the vehicle air-conditioning compressor of the embodiment as long as the features and functions of the present invention can be realized.
[Brief description of the drawings]
FIG. 1 is an external side view of a vehicle air-conditioning compressor according to an embodiment of the present invention.
FIG. 2 is a diagram showing a flow of an air conditioning refrigerant.
3A is a sectional view taken along line III-III of FIG. 1, and FIG. 3B is a sectional view taken along line bb of FIG. 3A.
FIG. 4 is an enlarged view of a portion IV in FIG. 3 (b).
FIG. 5 is a view showing the operation of the trigger valve of FIG. 4;
FIG. 6 is a diagram for explaining a burn-in phenomenon of a compressor.
FIG. 7 is a view showing the operation of the vehicle air conditioner compressor according to the present embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Compressor 10 Housing 12 Low pressure port 13 High pressure port 14 Low pressure chamber 15 Low pressure passage 16 High pressure chamber 17 High pressure passage 18 Bypass passage 20 Trigger valve 21 Bush 22 Ball 23 Spring

Claims (3)

A compressor housing having a refrigerant storage space,
A refrigerant compression mechanism built into the compressor housing,
A refrigerant path that compresses the refrigerant flowing from the low-pressure port by the refrigerant compression mechanism and guides the refrigerant to the high-pressure port,
A bypass passage that bypasses at least a part of the refrigerant path and guides the refrigerant flowing from the low-pressure port to the high-pressure port,
A valve mechanism for closing the bypass passage when the compressor is operating and opening the bypass passage when the compressor is stopped. The vehicle air-conditioning compressor according to claim 1,
The compressor for a vehicle air conditioner, wherein the bypass passage is formed in the compressor housing. The vehicle air-conditioning compressor according to claim 1 or 2,
The valve mechanism includes a valve body that moves in a direction to close the bypass passage by a differential pressure between the low-pressure passage and the high-pressure passage, and a spring that applies a biasing force to the valve body in a direction to open the bypass passage. Vehicle air conditioning compressor.

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