JP2007178047A - Silencer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a silencer used in a refrigerating cycle of an air conditioner for a vehicle, preventing liquid refrigerant from returning into a compressor. <P>SOLUTION: This silencer 20 is provided with a first chamber 21 for absorbing refrigerant from a ceiling part 21b and a second chamber 22 communicating with the first chamber through a refrigerant return pipe 24. A lower end is opened on a bottom part 21a side of the first chamber 21, and an upper end is opened in the outside of the second chamber 22. A refrigerant/oil return pipe 25 having a refrigerant return port 25a in the vicinity of a ceiling part 22b of the second chamber 22 is arranged to pass through the first and second chambers 21, 22. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a silencer structure used in a refrigeration cycle of a vehicle air conditioner.

  Conventionally, in a refrigeration cycle of a vehicle air conditioner, a silencer is disposed in front of a compressor that compresses refrigerant to reduce the flow noise of the refrigerant sucked into the compressor. In general, the interior of this type of silencer is divided into two upper and lower chambers. The refrigerant introduced from the inlet pipe is expanded and silenced in the upper chamber, and this refrigerant is sent to the lower chamber through an extraction pipe passing through the upper and lower chambers. It is sent out to the outlet piping from the compressor to the compressor. The oil circulating with the refrigerant is guided to the lower chamber through an oil return hole provided below the upper chamber, and is returned from here to the outlet pipe.

In addition to this silencer, the refrigeration cycle is provided with a liquid tank for separating the refrigerant from gas and liquid, an accumulator, and the like in front of the compressor (see Patent Documents 1 and 2).
Japanese Utility Model Publication No. 5-69570 Japanese Patent Laid-Open No. 10-23201

  By the way, the refrigerant during the operation of the air conditioner is in a gas state before the compressor. However, if the low outside air temperature continues while the air conditioner is stopped, the refrigerant enters the low pressure line leading to the internal heat exchanger-(silencer)-compressor. The refrigerant accumulates and is sucked into the compressor as the liquid refrigerant at the time of startup, and the compressor may be damaged by the liquid compression.

  Since the silencer having the conventional structure described above has only a silencing function, the return of the liquid refrigerant cannot be prevented, and the liquid tank and accumulator are arranged in front of the internal heat exchanger. The accumulation could not be prevented.

  An object of the present invention is to provide a silencer capable of preventing liquid refrigerant from returning to the compressor.

  In order to achieve the above object, the invention of claim 1 is characterized in that a first chamber for sucking refrigerant from a ceiling portion by a refrigerant suction pipe, and the first chamber provided at an upper portion of the first chamber and communicated with the first chamber by a refrigerant return pipe. And a second chamber that has a lower end that opens to the bottom side of the first chamber, an upper end that opens to the outside from the ceiling side of the second chamber, and a ceiling portion of the second chamber. A refrigerant / oil return pipe having a refrigerant return port in the vicinity thereof is disposed so as to penetrate the first chamber and the second chamber.

  According to the above configuration, the refrigerant sucked from the ceiling of the first chamber can be expanded inside the first chamber, so that the flow noise can be silenced. In addition, since the sucked liquid refrigerant can be stored at the bottom of the first chamber, even if the liquid refrigerant accumulates in the low pressure line from the internal heat exchanger to the compressor while the air conditioner is stopped, The refrigerant is not sucked into the compressor, and damage to the compressor due to liquid compression can be prevented.

  First, a refrigeration cycle of a vehicle air conditioner equipped with the silencer of the present embodiment will be described.

  FIG. 4 is a system diagram showing a refrigeration cycle of the vehicle air conditioner according to the present embodiment. In this refrigeration cycle, carbon dioxide is used as a refrigerant, a compressor 1 that compresses the refrigerant, and a sub heat exchanger 2 that exchanges heat between the refrigerant compressed by the compressor 1 and air supplied to the passenger compartment. The outdoor heat exchanger 3 that exchanges heat between the refrigerant and the outside air, the indoor heat exchanger 4 that exchanges heat between the refrigerant and the conditioned air blown into the vehicle interior, and the indoor heat exchanger 4 The first expansion valve 5 that depressurizes the refrigerant to be decompressed, the accumulator 6 that gas-liquid separates the refrigerant, the gas-phase refrigerant sent from the accumulator 6, and the high pressure that has passed through the sub heat exchanger 2 or the outdoor heat exchanger 3 The internal heat exchanger 7 for exchanging heat with the refrigerant, the silencer 20 having the function of silencing the refrigerant returned to the compressor 1 and separating the gas and liquid, and the refrigerant heat-exchanged by the internal heat exchanger 7 are decompressed. Output to outdoor heat exchanger 3 The second expansion valve 8, the check valves 9 and 10 that prevent backflow to the outdoor heat exchanger 3, the refrigerant discharged from the outdoor heat exchanger 3, and the flow of refrigerant flowing into the outdoor heat exchanger 3 The three-way valve 11 for switching, the electromagnetic valve 12 for controlling the flow of refrigerant from the sub heat exchanger 2, the air mix door 13 for controlling the flow of conditioned air from a blower fan (not shown), and set by the passenger It is comprised from the control part which is not shown in figure which controls said each part according to an operation mode etc.

  Here, the compressor 1 obtains a driving force from a motor (not shown) or a vehicle driving device, compresses gas phase carbon dioxide, and discharges it as a high-temperature and high-pressure refrigerant.

  The sub heat exchanger 2 is disposed in the air conditioning duct and warms the conditioned air blown from the blower fan by the high-temperature and high-pressure refrigerant supplied from the compressor 1.

  The outdoor heat exchanger 3 absorbs heat by exchanging heat between the low-pressure refrigerant output from the second expansion valve 8 and the outside air during heating, and absorbs heat during cooling, and the high-temperature and high-pressure refrigerant output from the sub heat exchanger 2 and the outside air. The heat is exchanged to dissipate heat.

  The indoor heat exchanger 4 is a heat exchanger that is disposed in the air conditioning duct and exchanges heat with the conditioned air blown from the blower fan by the low-temperature and low-pressure refrigerant decompressed (expanded) by the first expansion valve 5. It also functions as an evaporator.

  The first expansion valve 5 decompresses (expands) the high-pressure refrigerant output from the internal heat exchanger 7 and outputs it to the indoor heat exchanger 4.

  The accumulator 6 gas-liquid separates the refrigerant discharged from the outdoor heat exchanger 3. Of these, only the refrigerant in the gas phase is sent to the internal heat exchanger 7, and the refrigerant in the liquid phase is temporarily stored.

  The internal heat exchanger 7 exchanges heat between the gas-phase refrigerant output from the accumulator 6 and the high-pressure refrigerant that has passed through the sub heat exchanger 2 or the outdoor heat exchanger 3 and sends the heat to the compressor 1.

  The second expansion valve 8 decompresses (expands) the high-pressure refrigerant sent from the sub heat exchanger 2 via the internal heat exchanger 7 and outputs the decompressed refrigerant to the outdoor heat exchanger 3.

  The check valve 9 prevents the refrigerant from flowing from the internal heat exchanger 7 to the outdoor heat exchanger 3.

  The check valve 10 prevents the refrigerant from flowing from the indoor heat exchanger 4 or the accumulator 6 to the three-way valve 11.

  The three-way valve 11 switches the valve so that the refrigerant flows from the outdoor heat exchanger 3 to the accumulator 6 in the heating mode and the refrigerant flows from the sub heat exchanger 2 to the outdoor heat exchanger 3 in the cooling mode.

  The solenoid valve 12 is controlled to be opened and closed by the control unit 14 and switches the flow path so that the refrigerant output from the sub heat exchanger 2 is guided to the internal heat exchanger 7.

  The air mix door 13 is disposed in front of the sub heat exchanger 2, and the opening degree (mixing ratio) is freely controlled by the control unit 14. When the conditioned air from the blower fan is heated by the sub heat exchanger 2, it is turned downward by a predetermined amount according to the required heating temperature at that time (mixing ratio 0 to 100%), and the conditioned air is heated. When not, it is controlled to rotate upward (mixing ratio 0%).

  Next, the structure and effect of the silencer 20 disposed between the compressor 1 and the internal heat exchanger 7 will be described.

  FIG. 1 is a schematic cross-sectional view of a silencer 20 according to this embodiment. The silencer 20 has a main body configured in a substantially cylindrical shape. The silencer 20 has a first chamber 21 that sucks and silences the refrigerant, and a second chamber that is disposed on the first chamber 21 and discharges only the gas refrigerant to the outside. Chamber 22.

  A refrigerant suction pipe 23 for sucking low-pressure refrigerant is attached to the first chamber 21 substantially vertically. The upper end of the refrigerant suction pipe 23 opens near the ceiling portion 21b of the first chamber 21, and the lower end opens outside the bottom portion 21a to connect to a refrigerant pipe (not shown) connected to the internal heat exchanger 7 (FIG. 4). Has been. A refrigerant return pipe 24 is attached between the first chamber 21 and the second chamber 22. The refrigerant return pipe 24 has an upper end that opens to the bottom 22 a side of the second chamber 22, and a lower end that opens to the ceiling 21 b side of the first chamber 21, so that the space between the first chamber 21 and the second chamber 22 is open. Communicate. Of the refrigerant sucked into the first chamber 21, only the gas refrigerant flows into the second chamber 22 by the refrigerant return pipe 24.

  In addition, a refrigerant / oil return pipe 25 that discharges refrigerant and oil to the compressor 1 (FIG. 4) side is disposed substantially vertically in the main body portion of the silencer 20 so as to penetrate the first chamber 21 and the second chamber 22. It is attached. The lower end of the refrigerant / oil return pipe 25 opens to the bottom 21 a side of the first chamber 21, and the upper end passes through the ceiling 22 b of the second chamber 22 and is connected to a refrigerant pipe (not shown) connected to the compressor 1. . The refrigerant / oil return pipe 25 has a refrigerant return port 25 a formed in the vicinity of the ceiling portion 22 b of the second chamber 22.

  In the above configuration, the refrigerant (mixed refrigerant of gas refrigerant and liquid refrigerant) sent from the internal heat exchanger 7 is sucked into the first chamber 21 through a refrigerant suction pipe 23 from a refrigerant pipe (not shown). At this time, since the refrigerant expands inside the first chamber 21, the flow noise is muted. Of the sucked refrigerant, the gas refrigerant flows into the second chamber 22 through the refrigerant return pipe 24, and the liquid refrigerant is stored in the bottom 21 a of the first chamber 21 together with the oil. Here, the oil stored in the bottom 21a of the first chamber 21 together with the liquid refrigerant is sucked from the lower end of the refrigerant / oil return pipe 25 and discharged to the compressor 1 together with the gas refrigerant. On the other hand, the gas refrigerant flowing into the second chamber 22 is sucked from a refrigerant return port 25 a formed in the refrigerant / oil return pipe 25 and discharged together with oil to the compressor 1.

  Thus, according to the silencer 20 of the present embodiment, the refrigerant sucked from the ceiling portion 21b of the first chamber 21 is not only expanded and silenced, but also the liquid refrigerant is stored in the bottom portion 21a of the first chamber 21. can do. For this reason, even when the air temperature is low and the outside air temperature is low and the liquid refrigerant accumulates in the low pressure line leading to the internal heat exchanger 7-(silencer 20)-compressor 1, the liquid refrigerant may be sucked into the compressor 1. In addition, damage to the compressor 1 due to liquid compression can be prevented. In the present embodiment, since the refrigerant return pipe and the oil return pipe are shared, the number of parts can be reduced, and the assembly workability can be improved.

  When the operation of the system is started and the compressor 1 is activated and the gas refrigerant warmed by the internal heat exchanger 7 is sucked into the silencer 20, the liquid refrigerant accumulated inside by receiving heat from the gas refrigerant is In order to gasify, it is discharged from the refrigerant / oil return pipe 25 through the refrigerant return pipe 24 through the refrigerant return port 25a.

  In the above-described embodiment, an example in which the refrigerant suction pipe 23 is attached from the first chamber 21 side has been described. However, as shown in FIG. 2, the refrigerant suction pipe 23A may be attached from the second chamber 22 side. The refrigerant suction pipe 23A shown in FIG. 2 is attached substantially vertically so as to pass through the first chamber 21 from the second chamber 22, and the upper end opens to the outside of the bottom ceiling portion 22b, and the internal heat exchanger 7 (FIG. It is connected to a refrigerant pipe (not shown) connected to 4), and the lower end is opened near the ceiling portion 21b of the first chamber 21. Further, as shown in FIG. 3, a refrigerant / oil return pipe 25A having a substantially U-shape on the first chamber 21 side is provided, and gas refrigerant is sucked from an end portion opened on the ceiling portion 21b side of the first chamber 21. However, the oil may be sucked from the oil return hole 26 at the bent portion.

  In addition, in the silencer 20 of the said embodiment, although the 1st chamber 21 and the 2nd chamber 22 are the structures integrated, if it connects with the refrigerant | coolant return pipe 24, the 1st chamber 21 and the 2nd chamber 22 may be separated.

  Moreover, the structure where the edge part connected to the exterior of the refrigerant | coolant suction pipes 23 and 23A and the refrigerant | coolant / oil return pipes 25 and 25A was opened outside from the side surface of the silencer main-body part may be sufficient.

It is a schematic sectional drawing of the silencer concerning embodiment. It is a schematic sectional drawing of the silencer which attached the refrigerant | coolant suction pipe from the 2nd chamber side. It is a schematic sectional drawing of the silencer which provided the refrigerant | coolant / oil return pipe | tube which made the shape of the 1st chamber side the substantially U shape. It is a systematic diagram which shows the refrigerating cycle of the vehicle air conditioner which concerns on embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Compressor 2 ... Sub heat exchanger 3 ... Outdoor heat exchanger 4 ... Indoor heat exchanger 5 ... 1st expansion valve 6 ... Accumulator 7 ... Internal heat exchanger 8 ... 2nd expansion valve 9 ... Check valve 10 ... Reverse Stop valve 11 ... Three-way valve 12 ... Solenoid valve 13 ... Air mix door 14 ... Control unit 20 ... Silencer 21 ... First chamber 21a ... Bottom (first chamber)
21b ... Ceiling (first room)
22 ... Second chamber 22a ... Bottom (second chamber)
22b ... Ceiling (second room)
23, 23A ... Refrigerant suction pipe 24 ... Refrigerant return pipe 25, 25A ... Refrigerant / oil return pipe 25a ... Refrigerant return port 26 ... Oil return hole

Claims (1)

A first chamber (21) for sucking refrigerant from the ceiling (21b) by a refrigerant suction pipe (23), and the first chamber (21) provided by an upper part of the first chamber and by a refrigerant return pipe (24). A silencer comprising a second chamber (22) in communication,
The lower end opens to the bottom (21a) side of the first chamber (21), the upper end opens to the outside from the ceiling (22b) side of the second chamber (22), and the second chamber (22) A refrigerant / oil return pipe (25) having a refrigerant return port (25a) in the vicinity of the ceiling (22b) is disposed so as to penetrate the first chamber (21) and the second chamber (22). Silencer (20) featuring.

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