JP2012159180A - Expansion valve and heat pump type air conditioner using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an expansion valve in which generation of noise due to cavitation is prevented when used as a throttle valve to make refrigerant flow reversibly, and a heat pump type air conditioner using the expansion valve.SOLUTION: The expansion valve has a valve box 2, a set of refrigerant piping connection ports 5, 6, and a separation wall 7 dividing an in-valve box refrigerant path connecting these refrigerant piping connection ports 5, 6 into two paths longitudinally, and a valve bore 13 and valve seats 14, 15 are formed on the separation wall 7. Further, valve chambers 9, 11 are formed on both sides with the partition wall 7 sandwiched therebetween and needle valves 8, 10 are arranged in the respective valve chambers 9, 11. The needle valves 8, 10 form a pair and are arranged coaxially with the valve bore 13. In addition, it is configured such that when one of the needle valves 8, 10 performs throttling action, the other of the needle valves 8, 10 is maintained in a full-open state.

Description

  The present invention relates to an expansion valve that reversibly circulates a refrigerant and a heat pump air conditioner using the expansion valve, and more particularly to a technique for improving flow rate characteristics in a bidirectional flow of the refrigerant.

  An expansion valve using a conventional needle valve has a refrigerant inlet / outlet on a side wall 102 of a substantially cylindrical valve box 101, as shown in FIGS. 7 (a) and 7 (b). One refrigerant pipe connection port 103 is provided, and the other refrigerant pipe connection port 105 is provided on the bottom wall 104. The refrigerant pipe connection ports 103 and 105 are connected to the entrance / exit pipes 103a and 105a, respectively. A space in the valve box 101 that connects the refrigerant pipe connection ports 103 and 105 is formed as a valve chamber 106. The valve chamber 106 accommodates a needle valve 107 whose tip is formed in a tapered shape. A valve hole 108 is formed at the center of the bottom wall 104, and an end of the valve hole 108 on the valve chamber 106 side is formed as a valve seat 109. An example of such an expansion valve is the expansion valve described in Patent Document 1.

  The expansion valve configured as described above has a variable opening throttle 110 between the needle valve 107 and the valve seat 109 when the needle valve 107 is moved forward and backward in the axial direction by a pulse motor (not shown). Is formed.

  Therefore, in this expansion valve, when the liquid refrigerant is introduced from the refrigerant pipe connection port 103 as shown by the solid line arrow in FIG. After being throttled at, the refrigerant flows out from the refrigerant pipe connection port 105 via the valve chamber 106. On the other hand, in this expansion valve, when the liquid refrigerant is introduced from the refrigerant pipe connection port 105 as shown by the broken line arrow in FIG. 7B, the liquid refrigerant introduced from the refrigerant pipe connection port 105 After being squeezed at, the refrigerant flows out from the refrigerant pipe connection port 103 through a narrow passage 111 and a valve hole 108 formed between the tip of the needle valve 107 and the valve hole 108.

  The expansion valve is used in such a manner that the flow direction of the refrigerant is switched reversibly. In any of the flow directions, the expansion valve is used as a pressure reducing valve for reducing the pressure of the high-pressure liquid refrigerant to a low pressure. May be used as such a pressure reducing valve, and may be used as a refrigerant flow rate control valve that simply adjusts the refrigerant flow rate in the other flow direction. The former use mode is, for example, a case where it is used for a liquid pipe in an integrated heat pump type air conditioner, and Patent Document 2 can be listed as such a conventional example. Moreover, the latter usage mode is, for example, a case where it is used for a liquid pipe of an indoor unit in a so-called multi-type heat pump type air conditioner in which a plurality of indoor units are connected to one outdoor unit. As a conventional example, Patent Document 3 can be listed.

Japanese Patent Laid-Open No. 2005-155561 Japanese Patent Laid-Open No. 2007-32980, FIG. Japanese Patent Laid-Open No. 2008-275195, FIG.

  By the way, in such an expansion valve, when the liquid refrigerant is introduced from the refrigerant pipe connection port 103, the liquid refrigerant introduced from the refrigerant pipe connection port 103 passes through the throttle portion 110 as described above, and then the needle valve. It passes through a narrow passage 111 formed between the tip of 107 and the valve hole 108. For this reason, a local pressure drop occurs in the narrow passage 111, which causes a problem that cavitation occurs and noise is likely to occur.

  In this expansion valve, when the liquid refrigerant is introduced from the refrigerant pipe connection port 105, the liquid refrigerant introduced from the refrigerant pipe connection port 103 passes through the throttle portion 110 and forms a wide space. Therefore, the local pressure drop as described above does not occur after passing through the throttle portion 110, and there is no possibility of noise generation due to the occurrence of cavitation.

  As described above, when the conventional expansion valve using a needle valve is used by reversibly circulating the refrigerant, cavitation occurs when the refrigerant is circulated in one direction, thereby generating noise. .

  The present invention has been made in view of such circumstances, and in the case of using a refrigerant as a throttle valve in a reversible manner, an expansion valve that prevents generation of noise due to cavitation and the same are used. An object is to provide a heat pump type air conditioner.

  The invention according to claim 1 relates to an expansion valve, and divides a set of refrigerant pipe connection ports forming an entrance and an opening and a space portion in a valve box communicating between the refrigerant pipe connection ports into front and rear. A partition wall partitioned into a partition wall, a valve hole formed in the partition wall, a valve seat formed on both sides of the valve hole in the partition wall, a valve chamber formed on both sides across the partition wall, and each valve chamber And a pair of needle valves which are formed in a tapered shape in a portion facing the valve seat, and the pair of needle valves are arranged coaxially and symmetrically and integrally with the valve hole therebetween The gist of the invention is that when one needle valve performs a throttling action, the other needle valve is held in a fully open state.

  According to the said structure, when one needle valve performs a throttle action according to the distribution direction of a refrigerant | coolant, it is comprised so that the other needle valve may be hold | maintained in a full open state. Therefore, when the refrigerant is used in a reversible manner, if the refrigerant is circulated from the fully open needle valve side to the needle valve side constituting the throttle portion, the refrigerant that has passed through the throttle portion forms a wide space. Therefore, the refrigerant after throttling does not pass through a narrow passage. Thereby, the local pressure drop in a narrow passage as in the conventional case is suppressed, and the generation of noise due to cavitation is suppressed.

  According to a second aspect of the present invention, in the expansion valve according to the first aspect, the pair of needle valves is configured such that one needle valve is advanced and retracted with respect to the valve seat by a pulse motor, and the other needle The gist of the valve is that the tip is attached so that the tip of the valve is elastically always pressed against the tip of the one needle valve.

  According to the said structure, the front-end | tip part of the other needle valve is always elastically pressed with respect to the front-end | tip part of one needle valve by the elastic body. For this reason, by moving the one needle valve back and forth with respect to the valve seat by a single pulse motor, the other needle valve can also be operated integrally. In addition, since the pair of needle valves has a structure in which the tip of the other needle valve is always elastically pressed against the tip of the one needle valve, two closing valves can be easily sandwiched between the valve holes. Can be combined.

  The gist of the invention according to claim 3 is that, in the expansion valve according to claim 1, the pair of needle valves are coupled to each other at their distal ends so as to be able to operate integrally. .

  According to the above configuration, since the pair of needle valves are coupled to each other at their distal ends so that the pair of needle valves can be integrally operated, both needle valves can be directly operated by a single motor. it can. Moreover, since it couple | bonds together in the front-end | tip part of both, a pair of needle valves can be easily combined in the state which pinched | interposed the valve hole.

  According to a fourth aspect of the present invention, in the expansion valve according to the third aspect, the pair of needle valves are joined by press-fitting and fitting a tip of one needle valve into a hole formed in the other needle valve. It is a summary.

  According to the above configuration, the pair of needle valves are coupled to each other by a method of press-fitting at their tip portions, so that the pair of needle valves can be integrally operated with a simple configuration.

  The invention according to claim 5 is a heat pump type air conditioner in which an expansion valve is used as a throttle valve combined with air conditioning by circulating a refrigerant reversibly during cooling operation and heating operation, The gist is that the expansion valve according to any one of claims 1 to 4 is used as the expansion valve.

  According to the said structure, since the expansion valve of any one of Claims 1-4 is used as a throttle valve combined with air conditioning, a refrigerant | coolant is distribute | circulated reversibly at the time of air_conditionaing | cooling operation and heating operation. However, the generation of noise due to cavitation is suppressed.

  The invention according to claim 6 is the heat pump type air conditioner according to claim 5, wherein the heat pump type air conditioner has a plurality of indoor units connected in parallel to one outdoor unit. The expansion valve is connected to the liquid pipe side of the indoor heat exchanger in each indoor unit, functions as a pressure reducing valve during cooling operation, and reduces the amount of refrigerant circulating through each indoor unit during heating. The gist is that it is configured to function as a flow control valve to be controlled.

  According to the said structure, the heat pump type air conditioner of Claim 5 is what is called a multi-type heat pump type air conditioner with which the several indoor unit was connected in parallel with respect to one outdoor unit. And since the above-mentioned expansion valve in which the generation | occurrence | production of the noise by cavitation was suppressed is used as an expansion valve used for an indoor unit, a quiet driving | operation can be performed in any driving | operation of air conditioning.

  According to the expansion valve of the present invention, when the refrigerant is used while being reversibly circulated, if the refrigerant is allowed to flow from the fully open needle valve side to the needle valve side constituting the throttle portion, the refrigerant passing through the throttle portion is wide. Since the refrigerant flows into the valve chamber forming a space, the refrigerant after the throttling action does not pass through the narrow passage. Thereby, the local pressure drop in a narrow passage as in the conventional case is suppressed, and the generation of noise due to cavitation is suppressed. Further, according to the heat pump type air conditioner according to the present invention, since such an expansion valve is used as a throttle valve for both air conditioning and heating, even if the refrigerant is circulated reversibly during cooling operation and heating operation. The generation of noise due to cavitation is suppressed.

It is principal part sectional drawing of the expansion valve which concerns on Embodiment 1 of this invention, Comprising: The state when a refrigerant | coolant distribute | circulates from a lower refrigerant | coolant piping connection port to an upper refrigerant | coolant piping connection port is shown. It is principal part sectional drawing of the same expansion valve, Comprising: The state when a refrigerant | coolant distribute | circulates in the direction opposite to FIG. It is a refrigerant circuit figure of the heat pump type air conditioner concerning the embodiment. It is a refrigerant circuit figure of the heat pump type air conditioner concerning Embodiment 2 of the present invention. It is principal part sectional drawing of the expansion valve which concerns on Embodiment 3 of this invention, Comprising: A state when a refrigerant | coolant distribute | circulates from a lower refrigerant | coolant piping connection port to an upper refrigerant | coolant piping connection port is shown. It is an expansion exploded view of the joint part of the 1st needle valve and the 2nd needle valve in the expansion valve. It is principal part sectional drawing of the expansion valve which concerns on a prior art example, Comprising: (a) shows a state when a refrigerant | coolant distribute | circulates from one refrigerant | coolant piping connection port to the other refrigerant | coolant piping connection port, (b) is a refrigerant | coolant ( The state when it distribute | circulates in the direction opposite to a) is shown.

(Embodiment 1)
Hereinafter, the expansion valve according to Embodiment 1 of the present invention will be described with reference to FIGS. 1 and 2.

In the following description, the vertical direction or the horizontal direction refers to the direction shown in FIGS.
In the expansion valve 1 according to this embodiment, refrigerant pipe connection ports 5 and 6 are provided above and below a side wall 3 in a substantially cylindrical valve box 2. The refrigerant pipes 5a and 6a are connected to the refrigerant pipe connection ports 5 and 6, respectively. Further, in the valve box 2, a space portion that connects the refrigerant pipe connection port 5 and the refrigerant pipe connection port 6 is formed, so that the space portion is divided into two in the front-rear direction (in this case, the vertical direction), that is, A partition wall 7 extending in the horizontal direction is provided so as to be divided into an upper space part communicating with the refrigerant pipe connection port 5 and a lower space part communicating with the refrigerant pipe connection port 6. These upper and lower spaces are formed as valve chambers 9 and 11 where needle valves 8 and 10 are arranged, respectively. In the following specification, the first needle valve 8 refers to the needle valve disposed in the upper space, and the second needle valve 10 refers to the needle valve disposed in the lower space. And The first valve chamber 9 refers to the upper space portion, and the second valve chamber 11 refers to the lower space portion.

  The partition wall 7 is formed with a valve hole 13 so that the throttle portions 16 and 17 are formed by the operation of the first needle valve 8 and the second needle valve 10. The upper and lower ends of the valve hole 13 are formed as a valve seat 14 and a valve seat 15.

  The first needle valve 8 and the second needle valve 10 are respectively formed so that throttle portions 16 (see FIG. 1) and 17 (see FIG. 2) are formed between the valve seat 14 and the valve seat 15, respectively. Tapered taper portions 8 a and 10 a are formed at the tip of the first needle valve 8, and the first needle valve 8 and the second needle valve 10 are formed coaxially with the valve hole 13.

  The first needle valve 8 is formed in a cylindrical portion 8b above the tapered portion 8a, and the cylindrical portion 8b is directly connected to a pulse motor (not shown) via a bearing portion (not shown). Further, the expansion valve 1 is configured such that the first needle valve 8 advances and retreats in the axial direction with respect to the valve seat 14 by the driving of the pulse motor, and a throttle portion 16 having a variable opening degree is formed. In addition, the opening degree of the throttle part 16 in the expansion valve 1 is controlled so as to correspond to an operation mode and a load state of an air conditioner or the like in which the expansion valve 1 is used.

  The second needle valve 10 is formed with a tapered portion 10a symmetrically with the first needle valve 8 and a columnar portion 10b continuous below the tapered portion 10a. In addition, a small-diameter cylindrical body portion 10c is formed on the upper portion of the tapered portion 10a so that the upper surface of the cylindrical body portion 10c is always pressed against the lower surface of the tapered 8a portion of the first needle valve 8. Thus, it is elastically pressed by an elastic body 18 such as a spring spring. The elastically pressed configuration is to follow the first needle valve 8 to move the second needle valve 10 up and down integrally with the first needle valve 8, and to the valve box 2 This is to facilitate the incorporation into the inside. The second needle valve 10 moves up and down together with the first needle valve 8 and moves forward and backward with respect to the valve seat 15 so that a variable throttle portion 17 is formed between the second needle valve 10 and the valve seat 15. Yes.

  In order to smoothly move the second needle valve 10 up and down, that is, in order to smoothly advance the vertical movement of the cylindrical portion 10b of the second needle valve 10 and the expansion and contraction operation of the elastic body 18 formed of a coil spring, A cylindrical guide wall 20 is formed above the wall 19. The inner diameter of the guide wall 20 is slightly larger than the outer diameter of the cylindrical portion 10b so that the second needle valve 10 is guided by the inner surface of the cylindrical portion 10b and can be smoothly moved up and down. The outer diameter of the coil spring constituting the elastic body 18 is formed to be slightly smaller than the inner diameter of the guide wall 20 so that the outer diameter of the coil spring can be expanded and contracted in a stable posture within the guide wall 20.

  Further, the first needle valve 8 and the second needle valve 10 are configured in such a manner that when one needle valve performs a throttling action, the other needle valve is held in a fully opened state. . This will be described more specifically. FIG. 1 is a state diagram in the case where the refrigerant flows in from the lower refrigerant pipe connection port 6 as shown by the solid line arrow and the refrigerant squeezed by the throttle portion 16 flows out from the upper refrigerant pipe connection port 5. . In this case, the first needle valve 8 performs a throttling action, and the second needle valve 10 is fully opened. Further, in FIG. 2, the refrigerant flows in from the upper refrigerant pipe connection port 5 as shown by the broken line arrow, and the refrigerant squeezed by the throttle portion 17 flows out from the lower refrigerant pipe connection port 6, as opposed to the case of FIG. 1. FIG. In this case, the second needle valve 10 performs a throttling action and the first needle valve 8 is fully open. Further, as shown in these drawings, the expansion valve 1 is configured to allow the refrigerant to flow from the throttle part side in the fully open state to the throttle part side in the throttle state.

The expansion valve 1 having the above configuration is used, for example, so as to perform a so-called expansion stroke in which the high-pressure liquid refrigerant is reduced to a low pressure in both directions in which the refrigerant is circulated reversibly.
Such a use example is, for example, a case where it is used in an integrated heat pump type air conditioner, and its refrigerant circuit is shown in FIG.

  In this refrigerant circuit, a four-way switching valve 32 is connected between the discharge port and the suction port of the compressor 31, and the outdoor heat exchanger 33, the expansion valve 1, the indoor heat is connected between the switching ports of the four-way switching valve 32. The exchangers 34 are sequentially connected. In this case, the refrigerant pipe 6a connected to the refrigerant pipe connection port 6 below the side wall of the expansion valve 1 is connected to the outdoor heat exchanger 33, and the refrigerant pipe connected to the refrigerant pipe connection port 5 above the side wall. 5a is connected to the indoor heat exchanger 34. In addition, although the connection direction of the expansion valve 1 is functionally the same even if the connection direction is reversed, it is assumed that the connection is made in this way in order to facilitate later explanation.

  And at the time of air_conditionaing | cooling operation, the four-way switching valve 32 is switched and operated by the position of a solid line, and a refrigerant | coolant is shown by the solid line arrow, the compressor 31, the four-way switching valve 32, the outdoor heat exchanger 33, It is circulated with the expansion valve 1, the indoor heat exchanger 34, the four-way switching valve 32, and the compressor 31. Then, by causing the expansion valve 1 to function as a throttle valve that reduces pressure, the outdoor heat exchanger 33 acts as a condenser and the indoor heat exchanger 34 acts as an evaporator, whereby indoor air is exchanged with room heat. Cooled by the vessel 34. In this case, the refrigerant flows through the expansion valve 1 as indicated by the solid line arrows shown in FIG.

  Further, during the heating operation, the four-way switching valve 32 is operated by being switched to the position of the broken line, so that the refrigerant is, as indicated by the broken-line arrow, the compressor 31, the four-way switching valve 32, the indoor heat exchanger 34, It is circulated with the expansion valve 1, the outdoor heat exchanger 33, the four-way switching valve 32, and the compressor 31. Then, by causing the expansion valve 1 to function as a throttle valve for reducing the pressure, the indoor heat exchanger 34 functions as a condenser and the outdoor heat exchanger 33 functions as an evaporator, whereby the indoor air is converted into the indoor heat exchanger. 34 is heated. In this case, the refrigerant flows through the expansion valve 1 as indicated by the broken line arrows shown in FIG.

Next, the operation of the expansion valve 1 according to the present embodiment will be described. In addition, description of the following operation | movement demonstrates as an example the case where it uses for the heat pump type air conditioner shown in FIG.
During the cooling operation, the refrigerant flows as indicated by solid arrows in FIG. The refrigerant condensed and liquefied by the outdoor heat exchanger 33 flows into the second valve chamber 11 from the refrigerant pipe 6 a, is decompressed by the throttle portion 16 via the valve hole 13, and passes through the first valve chamber 9 to be refrigerant pipe. It flows out toward the indoor heat exchanger 34 from 5a. In this case, after passing through the throttle portion 16, it flows out into the first valve chamber 9 which is a wide space portion without passing through a narrow passage as in the prior art. For this reason, it does not receive a local pressure drop after passing through the throttle portion 16, and the occurrence of cavitation is suppressed. Therefore, a quiet operation can be performed.

  Moreover, at the time of heating operation, a refrigerant | coolant distribute | circulates like the broken-line arrow in FIG. The refrigerant condensed and liquefied in the indoor heat exchanger 34 flows into the first valve chamber 9 from the refrigerant pipe 5 a, is decompressed by the throttle portion 17 through the valve hole 13, and passes through the second valve chamber 11 to form the refrigerant pipe. It flows out toward the outdoor heat exchanger 33 from 6a. In this case, after passing through the throttle part 17, it flows out into the second valve chamber 11 which is a wide space part without passing through a narrow passage as in the prior art. For this reason, it does not receive a local pressure drop after passing through the throttle portion 17 and the occurrence of cavitation is suppressed. Therefore, a quiet operation can be performed.

Since the expansion valve according to the present embodiment is configured as described above, the following effects can be obtained.
(1) When one needle valve 8 or 10 performs a throttling action according to the refrigerant flow direction, the other needle valve 10 or 8 is configured to be kept fully open. Therefore, when the refrigerant is used while being reversibly circulated, if the refrigerant is allowed to flow from the fully opened needle valves 10 and 8 side to the needle valves 8 and 10 constituting the throttle portion, the refrigerant having passed through the throttle portions 16 and 17 Since the refrigerant flows into the valve chambers 9 and 11 forming a wide space, the refrigerant after the throttling action does not pass through the narrow passage. Thereby, the local pressure drop in a narrow passage is not received as in the conventional case, and the generation of noise due to cavitation is suppressed.

  (2) The pair of needle valves 8 and 10 is configured such that one needle valve 8 is connected to a pulse motor (not shown) and is advanced and retracted with respect to the valve seat 14 by the pulse motor. The tip of the other needle valve 10 is attached to the tip of the needle so that it is always pressed elastically. Therefore, the other needle valve 10 can be operated integrally with the needle valve 8 by advancing and retracting one needle valve 8 with respect to the valve seat 14 by a single pulse motor.

  (3) Since the pair of needle valves 8 and 10 has a structure in which the tip of the other needle valve 10 is always pressed against the tip of one needle valve 8 by the elastic body 18, the valve hole 13. It is possible to easily combine the two needle valves 8 and 10 with a gap therebetween.

Moreover, since the heat pump type air conditioner according to Embodiment 1 is configured as described above, the following effects can be achieved.
(4) Since the expansion valve 1 configured as described above is used as a throttle valve for both air conditioning and heating, noise is generated by cavitation even when refrigerant is circulated reversibly during cooling operation and heating operation. It is suppressed.

(Embodiment 2)
Next, Embodiment 2 will be described with reference to FIG.
The second embodiment is a modification of the air conditioner as an application example of the expansion valve according to the first embodiment. That is, the expansion valve 1 functions as a pressure reducing valve during cooling operation, and functions as a flow control valve that controls the amount of refrigerant circulating through each indoor unit during heating. Note that the same reference numerals are used for the same components as those in the first embodiment, and the description of the components is omitted or simplified.

  The air conditioner according to Embodiment 2 uses a plurality of (in this case, three) indoor units 60 in parallel with one outdoor unit 40 using the liquid side communication pipe 51 and the gas side communication pipe 52. Is a so-called multi-type heat pump air conditioner connected to In this figure, the liquid side connecting pipe 51 and the gas side connecting pipe 52 are shown as common pipes for each indoor unit 60, but this pipe is connected to each indoor unit 60 independently and in parallel. As the piping, the indoor units 60 may be connected to the single outdoor unit 40 in parallel. Further, in the following description, it is simply expressed as the liquid side communication pipe 51 or the gas side communication pipe 52, but this expression includes the case where they are connected in parallel in this way.

  The outdoor unit 40 has a four-way switching valve 42 connected to the discharge port and the suction port of the compressor 41, and one switching port of the four-way switching valve 42 is connected to the liquid via the outdoor heat exchanger 43 and the outdoor expansion valve 44. The side connection pipe 51 is connected. A conventional general expansion valve is used as the outdoor expansion valve 44. The other switching port of the four-way switching valve 42 is connected to the gas side communication pipe 52.

  The indoor unit 60 includes an indoor heat exchanger 61 and an indoor expansion valve connected to the liquid side communication pipe 51 side of the indoor heat exchanger 61. The indoor unit 60 is a first embodiment as an indoor expansion valve. The expansion valve 1 according to the above is used as it is. Incidentally, the connection method of the expansion valve 1 in this case is similar to the case of the first embodiment, in order to simplify the following description, the refrigerant pipe 6a connected to the lower refrigerant pipe connection port 6 is liquid. It is assumed that the refrigerant pipe 5 a connected to the side communication pipe 51 and connected to the upper refrigerant pipe connection port 5 is connected to the indoor heat exchanger 61. The other end of the indoor heat exchanger 61 is connected to the gas side communication pipe 52.

  This multi-type heat pump type air conditioner is operated by switching the four-way switching valve 42 to the position of the solid line during the cooling operation. Further, during this cooling operation, the outdoor expansion valve 44 is fully opened, and the indoor expansion valve, that is, the expansion valve 1 is caused to function as a throttle valve for reducing the pressure.

  During the cooling operation, the refrigerant discharged from the compressor 41 passes through the four-way switching valve 42 and expands in the outdoor heat exchanger 43, the outdoor expansion valve 44, the liquid side communication pipe 51, and the indoor units 60 connected in parallel. The valve 1, the indoor heat exchanger 61, and the gas side communication pipe 52 are sequentially circulated to return to the compressor 41 via the four-way switching valve 42. In each expansion valve 1, the opening degree of the throttle portion 16 is controlled so as to correspond to the cooling load in each indoor unit 60. As a result, the outdoor heat exchanger 43 acts as a condenser and the indoor heat exchanger 61 acts as an evaporator, so that each indoor unit 60 cools each indoor air.

  Next, at the time of heating operation, the four-way switching valve 42 is operated by being switched to the position of the broken line. In addition, during this heating operation, the outdoor expansion valve 44 is operated so as to function as a throttle valve that depressurizes the high-pressure liquid refrigerant, and the indoor expansion valve, that is, the expansion valve 1 is adapted to the heating load in each indoor unit 60. It is made to function as a throttle valve that controls the amount of refrigerant circulating in each indoor unit 60.

  During the heating operation, the refrigerant discharged from the compressor 41 passes through the four-way switching valve 42, the gas side communication pipe 52, the indoor heat exchanger 61 and the expansion valve 1 of each indoor unit 60 connected in parallel, the liquid side. The communication pipe 51, the outdoor expansion valve 44 of the outdoor unit 40, and the outdoor heat exchanger 43 are sequentially circulated and returned to the compressor 41 via the four-way switching valve 42. In each expansion valve 1, the opening degree of the throttle unit 17 is controlled so as to control the refrigerant flow rate corresponding to the heating load in each indoor unit 60. As a result, since the indoor heat exchanger 61 acts as a condenser and the outdoor heat exchanger 43 acts as an evaporator, each indoor unit 60 heats each indoor air.

The expansion valve 1 according to the present embodiment operates as follows when used in the multi-type heat pump type air conditioner illustrated in FIG.
Since the expansion valve 1 functions as an expansion valve that depressurizes the high-pressure liquid refrigerant during the cooling operation, the expansion valve 1 performs the same operation as in the first embodiment, and the refrigerant circulates as indicated by solid line arrows in FIG. That is, the refrigerant condensed and liquefied in the outdoor heat exchanger 43 flows into the second valve chamber 11 from the refrigerant pipe 6a through the liquid side connection pipe 51, is decompressed by the throttle unit 16 through the valve hole 13, and is The refrigerant flows out from the refrigerant pipe 5a toward the indoor heat exchanger 61 via the valve chamber 9. In this case, after passing through the throttle part 16, it flows out to the first valve chamber 9 which is a wide space without passing through a narrow passage as in the prior art, and therefore, after passing through the throttle part 16, it receives a local pressure drop as in the conventional case. And the occurrence of cavitation is suppressed. Therefore, a quiet operation can be performed.

  Next, during the heating operation, the outdoor expansion valve 44 functions as an expansion valve that depressurizes the high-pressure liquid refrigerant. Accordingly, the expansion valve 1 is in a state where it is connected in a liquid refrigerant circuit in which three indoor heat exchangers 61 are connected in parallel, and a throttle that controls the amount of refrigerant circulating through each indoor heat exchanger 61. Acts as a valve. In this case, the liquid refrigerant after passing through the indoor heat exchanger 61 flows into the first valve chamber 9 from the refrigerant pipe 5a and passes through the valve hole 13 as shown by the broken line arrow in FIG. The flow rate is controlled at 17 and flows out from the refrigerant pipe 6 a to the liquid side connecting pipe 51 through the second valve chamber 11. In this case, after passing through the throttle portion 17, it flows out into the second valve chamber 11 which is a wide space portion without passing through a narrow passage as in the prior art. The occurrence of cavitation is suppressed without being received. Therefore, a quiet operation can be performed.

Since the expansion valve according to the present embodiment is configured as described above, the effects (1) to (3) in the first embodiment can be achieved.
Moreover, in the multi-type heat pump type air conditioner according to this embodiment, the following effects can be achieved.

  (5) Since the multi-type heat pump air conditioner according to the second embodiment uses the expansion valve 1 of the first embodiment, noise due to cavitation is suppressed in the expansion valve 1 in any operation of cooling and heating. ing. Therefore, the indoor unit 60 of each room can be operated silently.

(Embodiment 3)
Next, an expansion valve according to Embodiment 3 will be described with reference to FIGS.
In this embodiment, the structure for operating the pair of needle valves integrally in the first embodiment is changed. Note that the same reference numerals are used for the same components as those in the first embodiment, and the description of the components is omitted or simplified.

  In the expansion valve according to this embodiment, as shown in FIGS. 5 and 6, a cylindrical protrusion 10 d having a smaller diameter is formed with respect to the cylindrical body portion 10 c at the tip of the second needle valve 10. On the other hand, a hole 8c for press-fitting the cylindrical protrusion 10d is provided on the tip surface of the tapered portion 8a of the first needle valve 8.

  In this embodiment, when the needle valves 8 and 10 are assembled into the valve box 2, the cylindrical protrusion 10d of the second needle valve 10 is press-fitted into the hole 8c of the first needle valve 8. The first needle valve 8 and the second needle valve 10 are combined so that the opening degree of the throttle portions 16 and 17 can be adjusted by a single pulse motor. 5 is a drawing corresponding to FIG. 1 according to the first embodiment, and is a drawing when the refrigerant flows from the lower refrigerant pipe connection port 6 to the upper refrigerant pipe connection port 5 as indicated by solid arrows. Therefore, in this figure, the throttle portion 17 is in a fully open state. In the invention according to this embodiment, since the coupling structure of the pair of needle valves 8 and 10 is a main part, the state diagram corresponding to FIG. 2 is omitted.

  Further, in this embodiment, as shown in FIG. 5, since the second needle valve 10 is coupled to the first needle valve 8 at the tip portion, it is like a spring spring as in the first embodiment. There is no need to provide an elastic body below the second needle valve 10, and its installation is omitted. Therefore, the length of the cylindrical guide wall 20 can be shortened as much as the installation of the elastic body can be omitted.

In the expansion valve according to the third embodiment, the pair of needle valves 8 and 10 operate as follows.
That is, in the expansion valve 1, the first needle valve 8 and the second needle valve 10 can be directly operated by operating a pulse motor (not shown) directly connected to the cylindrical portion 8b. Therefore, the opening degree of the throttle parts 16 and 17 is directly controlled by adjusting a single pulse motor.

Since the expansion valve according to Embodiment 3 is configured as described above, in addition to the effect of (1) in Embodiment 1, the following effect can be achieved.
(6) Since the pair of needle valves 8 and 10 are structured to be connected to each other by press-fitting at their tip portions, the press-fitting is performed when the needle valves 8 and 10 are assembled into the valve box 2. By doing so, the two needle valves 8 and 10 can be coupled with the valve hole 13 in between.

  (7) Further, the pair of needle valves 8 and 10 can be integrally operated by a simple coupling configuration in which the pair of needle valves 8 and 10 are coupled to each other by press-fitting at their tip portions. it can.

Further, when the expansion valve 1 according to the third embodiment is used in the integrated heat pump type air conditioner according to the first embodiment, the effect (4) in the first embodiment can be achieved.
(Modification)
The present invention can be modified as follows in the above embodiment.

In the multi-type heat pump air conditioner according to the second embodiment, the expansion valve 1 according to the third embodiment may be used.
In each embodiment, the connection direction of the expansion valve 1 is specified, but this connection may be made in the reverse direction as mentioned earlier. In this embodiment, the reason for specifying as described above is to match the meanings of the solid line arrows and the broken line arrows attached to the drawings.

  In the second embodiment, a conventional expansion valve is used as the outdoor expansion valve 44, but the expansion valve 1 according to the first or third embodiment may be used for this expansion valve. However, in this case, regarding the noise of the outdoor unit 40, since the noise of the compressor or the like is originally related to the noise problem in the outdoors, the meaning of using the expansion valve 1 of the present invention is diminished.

  In the third embodiment, the first needle valve 8 and the second needle valve 10 are coupled by press-fitting at their respective distal ends, but instead of this press-fitting, the distal end of the second needle valve 10 The cylindrical protrusion 10 d may be screwed to the first needle valve 8.

  DESCRIPTION OF SYMBOLS 1 ... Expansion valve, 2 ... Valve box, 5, 6 ... Refrigerant piping connection port, 7 ... Partition wall, 8 ... (1st) Needle valve, 8c ... Hole, 9 ... (1st) Valve chamber, 10 ... ( 2nd) Needle valve, 11 ... (2nd) Valve chamber, 13 ... Valve hole, 14, 15 ... Valve seat, 40 ... Outdoor unit, 60 ... Indoor unit.

Claims (6)

A partition wall that divides the space portion in the valve box (2) that communicates between the refrigerant pipe connection ports (5, 6) and the pair of refrigerant pipe connection ports (5, 6) that form an entrance and exit into two parts. (7), a valve hole (13) formed in the partition wall (7), valve seats (14, 15) formed on both sides of the valve hole (13) in the partition wall (7), and a partition wall ( 7) The valve chambers (9, 11) formed on both sides of the valve chamber (9) and a pair of valve chambers (9, 11) facing the valve seats (14, 15) are tapered. Needle valve (8, 10)
The pair of needle valves (8, 10) are arranged coaxially and are formed to operate symmetrically and integrally with the valve hole (13) in between, and further, one needle valve (8 or 10) is formed. The expansion valve is configured so that the other needle valve (10 or 8) is held in a fully opened state when the throttle operation is performed. The expansion valve according to claim 1,
The pair of needle valves (8, 10) is configured such that one needle valve (8) is advanced and retracted relative to the valve seat (14, 15) by a pulse motor,
The other needle valve (10) is attached so that the tip thereof is elastically always pressed against the tip of the one needle valve (8). The expansion valve according to claim 1,
The expansion valve is characterized in that the pair of needle valves (8, 10) are coupled to each other at their leading ends so as to be able to operate integrally. The expansion valve according to claim 3,
The pair of needle valves (8, 10) is joined by press-fitting and fitting the tip of one needle valve (10) into a hole (8c) formed in the other needle valve (8). An expansion valve. A heat pump air conditioner in which an expansion valve is used as a throttle valve for both air conditioning and heating by reversibly circulating a refrigerant during cooling operation and heating operation,
The expansion valve of any one of Claims 1-4 is used as said expansion valve. The heat pump type air conditioner characterized by the above-mentioned. In the heat pump type air conditioner according to claim 5,
This heat pump type air conditioner has a plurality of indoor units (60) connected in parallel to one outdoor unit (40),
The expansion valve is connected to the liquid pipe side of the indoor heat exchanger in each indoor unit (60), functions as a pressure reducing valve during cooling operation, and circulates refrigerant circulating in each indoor unit (60) during heating. A heat pump type air conditioner configured to function as a flow control valve for controlling the amount.

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