JP2012037224A - Refrigerant flow path switching unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To save power without generating noise caused by self-induced vibration.SOLUTION: This refrigerant flow path switching unit includes a flow path switching valve (51) having a first valve seat (52) and a movable valve element (56). In the first valve seat (52), first to third connection ports (A, B, C) are formed. In the movable valve element (56), a through-hole (57) is formed. The flow path switching valve (51) causes the first and second connection ports (A, B) to communicate with each other via the through-hole (57) in an air cooling state, and causes the first and third connection ports (A, C) to communicate with each other via a body space (55a) during an air heating operation.

Description

    The present invention relates to a refrigerant flow path switching unit.

    Conventionally, an air conditioner including an outdoor unit having a heat source side heat exchanger and a plurality of indoor units having a use side heat exchanger is known (see, for example, Patent Document 1). A refrigerant flow path switching unit serving as a BS unit is connected between the outdoor unit and each indoor unit.

    Specifically, the refrigerant flow switching unit is provided in a refrigerant circuit having an outdoor unit and a plurality of indoor units, and includes a refrigerant pipe and a plurality of solenoid valves provided on the refrigerant pipe. . In the refrigerant flow switching unit, the state in which the refrigerant evaporated in the indoor unit flows in and flows out toward the compressor in the outdoor unit and the refrigerant discharged from the compressor in the outdoor unit flows in by switching the electromagnetic valve. And it is comprised so that it may switch to the state which flows out toward an indoor unit. Thereby, as for an air conditioning apparatus, air_conditioning | cooling and heating switch separately for every indoor unit, ie, for every utilization side heat exchanger.

Japanese Patent Laid-Open No. 11-241844

    By the way, as described above, the refrigerant flow switching unit configured to be able to switch the refrigerant flow so that the cooling / heating operation can be switched for each use-side heat exchanger has a control valve such as an electromagnetic valve for switching the refrigerant flow. You will need more than one. For example, when an electromagnetic valve is used, the valve body undergoes self-excited vibration due to the relationship with the acting force of a spring provided in the valve body in a low refrigerant pressure state at a low load such as when the refrigerant flow is switched. There was a problem of waking up. This self-excited vibration causes a problem that noise (chattering sound) is generated in the refrigerant flow path switching unit. In addition, since it is necessary to energize the solenoid valve at all times, it has been disadvantageous for saving power.

    The present invention has been made in view of such a point, and an object of the present invention is to provide a refrigerant flow path switching unit that can save power without generating noise due to self-excited vibration. is there.

    1st invention is provided in the refrigerant circuit (10) which has a compressor (21), a heat-source side heat exchanger (22), and several utilization side heat exchangers (31), Each said utilization side heat exchanger Refrigerant flow path comprising a flow path switching valve (51) for switching the flow path of the refrigerant so that (31) communicates with either the discharge pipe (11) or the suction pipe (12) of the compressor (21) It is a switching unit.

    The flow path switching valve (51) includes a first connection port (A) connected to the use side heat exchanger (31) and a second connection port (B) connected to the suction pipe (12). ) And a third connection port (C) connected to the discharge pipe (11) includes a valve seat (52) opened in the valve seat surface (52b).

    Further, the flow path switching valve (51) is disposed so as to overlap the valve seat (52) and is rotatable around a predetermined axis orthogonal to the valve seat surface (52b) of the valve seat (52). A movable valve body (56) is provided in the internal space (55), the cooling state in which the movable valve body (56) is rotated to communicate the first and second connection ports (A, B), and the first And a valve body (54) for switching to a heating state in which the third connection ports (A, C) communicate.

    In the first aspect of the invention, when the movable valve body (56) rotates around a predetermined axis, the communication state between the first to third connection ports (A, B, C) is controlled. Specifically, when the first and second connection ports (A, B) communicate with each other, the cooling state is established, and when the first and third connection ports (A, C) communicate with each other, the heating state is established.

    According to the first aspect of the present invention, it is possible to eliminate various problems that occur when an electromagnetic valve is used as the flow path switching valve (51). Specifically, in a state where the refrigerant pressure is low at a low load, such as when the refrigerant flow is switched, in a conventional solenoid valve, the valve body undergoes self-excited vibration due to the relationship with the acting force of a spring provided on the valve body. There is a problem of waking up. This self-excited vibration causes a problem that noise (chattering noise) is generated in the refrigerant flow path switching unit.

    On the other hand, in the first invention, the flow switching valve (51) having the valve seat (52) and the movable valve element (56) is used, and the movable valve element (56) is rotated around a predetermined axis. Thus, since the communication state between the first to third connection ports (A, B, C) is switched, chattering noise does not occur as in the case of using an electromagnetic valve. Further, it is not necessary to energize constantly like a solenoid valve, and power saving can be achieved.

    According to a second aspect, in the first aspect, the movable valve body (56) includes a communication path (57) for communicating two adjacent connection ports (A, B).

    In the second aspect of the invention, the two connection ports (A, B) communicate with each other through the communication passage (57) of the movable valve body (56).

    In a third aspect based on the second aspect, the valve body (54) communicates the first and second connection ports (A, B) through the communication passage (57) in the cooling state, In the heating state, the first and third connection ports (A, C) are communicated with each other through the main body space (55a) outside the movable valve body (56) in the internal space (55). Is.

    In the third aspect, in the cooling state, the first and second connection ports (A, B) communicate with each other through the communication passage (57), and in the heating state, the first and third connections are established with the main body space (55a). Port (A, C) communicates.

    According to a fourth aspect of the present invention, in the second or third aspect, the movable valve body (56) has a sealing member (66) that closes a gap with the valve seat (52) at the periphery of the communication passage (57). It is provided.

    In the fourth aspect of the invention, the space between the communication path (57) and the outer side of the movable valve body (56) is sealed by the seal member (66).

    According to a fifth invention, in the first invention, the main body space outside the movable valve body (56) in the internal space (55) of the valve main body (54) in the cooling state in the valve seat (52). A bypass hole (58) for bypassing the refrigerant from the discharge pipe (11) to the suction pipe (12) through (55a) is formed.

    In the fifth aspect, in the cooling state, the refrigerant is bypassed from the discharge pipe (11) to the suction pipe (12) through the bypass hole (58).

    In the fifth aspect of the invention, it is possible to prevent the refrigerant from condensing in the discharge pipe (11) during the cooling operation. Specifically, if the discharge pipe (11) is closed during the cooling operation, the refrigerant condenses in the discharge pipe (11), and the condensed refrigerant accumulates in the flow path switching valve (51). There is a possibility that the switching of the switching valve (51) cannot be performed smoothly.

    On the other hand, in the fifth invention, the refrigerant is bypassed from the discharge pipe (11) to the suction pipe (12) via the bypass hole (58) during the cooling operation. The refrigerant will not condense. In addition, the refrigerant can be bypassed from the discharge pipe (11) to the suction pipe (12) simply by forming the bypass hole (58) in the valve seat (52), so there is no need to separately provide a bypass pipe. Is not complicated, which is advantageous for cost reduction.

    According to a sixth invention, in the first or fifth invention, the refrigerant circuit (10) is connected to a discharge side port connected to the discharge pipe (11) and to the heat source side heat exchanger (22). A first three-way valve (24) having a heat source side port and a suction side port connected to the suction pipe (12); a discharge side port connected to the discharge pipe (11); 51) and a second three-way valve (25) in which a suction side port connected to the suction pipe (12) is formed, while the valve body (54) 2 The movable valve body (56) in the internal space (55) of the valve body (54) in a state where the use side port of the three-way valve (25) and the suction side port communicate with each other and the discharge side port is closed at the same time All the first to third connection ports (A, B, C) are connected through the main body space (55a) outside It is configured to be able to switch to a fully cooled state to be passed.

    In the sixth aspect of the invention, when all the plurality of use side heat exchangers (31) are operated in the cooling operation, the use side heat exchanger (31) is connected to the first connection port (A) of the flow path switching valve (51). By branching the inflowing refrigerant into the second and third connection ports (B, C), the pressure loss of the refrigerant flowing in the pipe is reduced.

    According to the present invention, using the flow path switching valve (51) having the valve seat (52) and the movable valve element (56), the movable valve element (56) is rotated around a predetermined axis, Since the communication state between the first to third connection ports (A, B, C) is switched, chattering noise does not occur unlike when a solenoid valve is used. Further, it is not necessary to energize constantly like a solenoid valve, and power saving can be achieved.

    According to the second and third inventions, since the communication passage (57) is formed in the movable valve body (56), it is only necessary to seal the periphery of the communication passage (57), and the switching power can be reduced. Can be planned.

    According to the fifth invention, in the cooling state, the refrigerant is bypassed from the discharge pipe (11) to the suction pipe (12) via the bypass hole (58), so that refrigerant condensation in the discharge pipe (11) is suppressed. can do. Further, since only the bypass hole (58) is formed in the valve seat (52), there is no need to separately provide a bypass pipe, the pipe can be simplified, and the cost can be reduced.

    According to the sixth aspect of the invention, when all of the plurality of use side heat exchangers (31) are operated in the cooling operation, the first connection port (A) of the flow path switching valve (51) from the use side heat exchanger (31) ) Is caused to branch into the second and third connection ports (B, C), so that the pressure loss of the refrigerant flowing in the pipe can be reduced.

FIG. 1 is a piping system diagram of a refrigerant circuit of a refrigeration apparatus according to an embodiment of the present invention. FIG. 2 is a longitudinal sectional view showing the configuration of the BS unit. FIG. 3 is a plan sectional view showing the position of the movable valve body of the flow path switching valve during the cooling operation. FIG. 4 is a cross-sectional plan view showing the position of the movable valve body of the flow path switching valve during heating operation. FIG. 5 is a plan cross-sectional view showing the position of the movable valve body of the flow path switching valve during the entire cooling operation. FIG. 6 is a piping system diagram of the refrigerant circuit for explaining the flow of the refrigerant during the entire heating operation. FIG. 7 is a piping system diagram of the refrigerant circuit for explaining the flow of the refrigerant during the entire cooling operation. FIG. 8 is a piping system diagram of the refrigerant circuit for explaining the flow of the refrigerant during the simultaneous heating / cooling operation.

    Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the following description of the preferred embodiment is merely illustrative in nature and is not intended to limit the present invention, its application, or its use.

    As shown in FIG. 1, the refrigeration apparatus according to the embodiment of the present invention constitutes an air conditioner (1) capable of individually heating or cooling a plurality of rooms. The air conditioner (1) is a so-called cooling / heating-free air conditioner that can be operated to heat one room and cool another room.

    The air conditioner (1) includes one outdoor unit (20), three indoor units (30, 30, 30), and three BS units (50, 50, 50) and a refrigerant circuit (10) connected by piping. The refrigerant circuit (10) performs a vapor compression refrigeration cycle in which the refrigerant circulates.

<Configuration of outdoor unit>
The outdoor unit (20) constitutes a heat source side unit, and includes a compressor (21), an outdoor heat exchanger (22), an outdoor expansion valve (23), a first three-way valve (24), and a second three-way valve (25 ). The compressor (21) is an inverter type compressor having a variable capacity. The outdoor heat exchanger (22) is a cross-fin heat exchanger and constitutes a heat source side heat exchanger. The outdoor expansion valve (23) is composed of, for example, an electronic expansion valve.

    The first and second three-way valves (24, 25) have a first port to a third port. The first three-way valve (24) has a first port connected to the discharge pipe (11) of the compressor (21), a second port connected to the outdoor heat exchanger (22), and a third port connected to the compressor (21). Connected to the suction pipe (12). In the second three-way valve (25), the first port (discharge port) is connected to the discharge pipe (11) of the compressor (21), and the second port (use side port) is connected to each BS unit (50). The third port (suction side port) is connected to the suction pipe (12) of the compressor (21). The first and second three-way valves (24, 25) have a state in which the third port is closed at the same time that the first and second ports communicate with each other (a state indicated by a solid line in FIG. 1), a second port and a third port. Can be switched to a state in which the first port is closed at the same time as is communicated with (a state indicated by a broken line in FIG. 1).

<Configuration of indoor unit>
The air conditioner (1) includes first to third indoor units (30). In the following description, the first to third indoor units (30) are referred to in order from the top of FIG. Each indoor unit (30) includes an indoor heat exchanger (31) and an indoor expansion valve (32). Each indoor heat exchanger (31) is a cross fin type heat exchanger, and constitutes a use side heat exchanger. Each indoor heat exchanger (31) has one end connected in parallel to the end of the liquid pipe (15). Each indoor expansion valve (32) is composed of, for example, an electronic expansion valve. Each indoor expansion valve (32) is provided on one end side of the corresponding indoor heat exchanger (31).

<Configuration of BS unit>
The air conditioner (1) includes first to third BS units (50) corresponding to the indoor units (30) described above. In the following description, the first to third BS units (50) will be referred to in order from the top of FIG. Each BS unit (50) includes a flow path switching valve (51). The flow path switching valve (51) has a refrigerant flow path so that each indoor heat exchanger (31) communicates with either the discharge pipe (11) or the suction pipe (12) of the compressor (21). The air conditioner (1) is switched between the cooling operation and the heating operation.

    The flow path switching valve (51) has a first connection port (A), a second connection port (B), and a third connection port (C) (see FIG. 3). The flow path switching valve (51) has a first connection port (A) connected to the indoor heat exchanger (31), a second connection port (B) connected to the suction pipe (12), and a third connection port (C ) Is connected to the second port of the second three-way valve (25). The flow path switching valve (51) has a heating state (state indicated by a solid line in FIG. 1) in which the first and third connection ports (A, C) communicate with each other and the second connection port (B) is closed, A cooling state (state indicated by a broken line in FIG. 1) in which the first and second connection ports (A, B) communicate with each other and the third connection port (C) is closed, and the first to third connection ports (A, B) , C) can be switched to an all-cooling state (see FIG. 7) in which all of them communicate.

    FIG. 2 is a longitudinal sectional view showing the configuration of the BS unit. As shown in FIG. 2, the BS unit (50) includes a flow path switching valve (51) and a motor (60). The drive shaft (61) of the motor (60) is attached to the movable valve body (56) of the flow path switching valve (51) via the gear box (62). The gear box (62) is covered with a gear cover (63). The motor (60) is formed of a stepping motor and can control the rotation angle of the movable valve body (56). Thereby, it is possible to perform control such that the movable valve body (56) is gradually opened to reduce the refrigerant sound when the valve is opened.

    The flow path switching valve (51) includes a first valve seat (52) and a second valve seat (53), and a valve body (54). The valve body (54) includes a movable valve body (56). The first and second valve seats (52, 53) are formed in a disk shape and are arranged to face each other with a predetermined gap. On the opposing surface side of the first and second valve seats (52, 53), fitting grooves (52a, 53a) are formed along the outer peripheral edge thereof. A cylindrical valve body (54) is fitted into the fitting grooves (52a, 53a). The valve body (54) includes an internal space (55) defined by the first and second valve seats (52, 53).

    Further, the opposing surfaces of the first valve seat (52) and the second valve seat (53), that is, the upper surface of the first valve seat (52) and the lower surface of the second valve seat (53) are flat valve seats. It is formed on the surface (52b, 53b).

    As shown in FIG. 3, the first to third connection ports (A, B, C) are formed in the first valve seat (52). One end of each of the first to third connection ports (A, B, C) opens to the valve seat surface (52b), and the openings of the first to third connection ports (A, B, C) are the same. The holes are arranged at predetermined angular intervals so that the respective hole centers are located on the virtual circle. Specifically, the openings of the second connection port (B) and the third connection port (C) are located on both sides of the opening of the first connection port (A), and the opening of the first connection port (A). And the opening of the second connection port (B) are set equal to the distance between the opening of the first connection port (A) and the opening of the third connection port (C).

    The first to third connection ports (A, B, C) extend in the thickness direction of the first valve seat (52) from the opening of the valve seat surface (52b) and then penetrate in the radial direction, and the other end Is open on the outer peripheral surface of the first valve seat (52). In FIG. 3, the first connection port (A) opens at the left end of the first valve seat (52), and the second and third connection ports (B, C) open at the right end.

    The first valve seat (52) has a small-diameter bypass hole (58) communicating with the second connection port (B) extending in the radial direction. The bypass hole (58) is for bypassing a small amount of refrigerant from the discharge pipe (11) to the suction pipe (12) in the cooling state, and will be described in detail later.

    As shown in FIG. 2, the second valve seat (53) is fitted with a bearing (not shown) in the center thereof, and the drive shaft (61) of the motor (60) is fitted into this bearing.

    The movable valve body (56) has a planar shape in a sector shape and is disposed in the internal space (55). And as for the said internal space (55), the outer side of the movable valve body (56) comprises the main body space (55a). The movable valve element (56) is rotatably provided around a predetermined axis that is orthogonal to the valve seat surface (52b, 53b), and is driven to rotate about the axis of the drive shaft (61) of the motor (60). To do. That is, the movable valve body (56) is displaced in the rotational direction with respect to the first valve seat (52). A pin (64) that rotatably supports the movable valve body (56) is provided on the lower surface side of the movable valve body (56).

    The movable valve body (56) is formed with a through hole (57) as a communication path. The through hole (57) and the main body space (55a) are used for switching the communication state between the first to third connection ports (A, B, C) of the first valve seat (52). For example, in FIG. 3, the valve body (54) has a through hole (57) positioned on the first and second connection ports (A, B) and between the first and second connection ports (A, B). It will be in the air-conditioning state which makes it communicate.

    When the movable valve body (56) rotates counterclockwise from the state of FIG. 3, the through hole (57) is positioned on the second connection port (B) as shown in FIG. It does not overlap the third connection port (A, C). In the valve body (54) of FIG. 4, the first and third connection ports (A, C) are opened to the body space (55a), and the space between the first and third connection ports (A, C) is the body space ( In 55a), the heating state communicates with each other.

    Further, when the movable valve body (56) rotates counterclockwise from the state of FIG. 4, the through holes (57) are connected to the first to third connection ports (A, B, C) as shown in FIG. It is designed not to overlap. In the valve body (54) of FIG. 5, the first to third connection ports (A, B, C) are opened to the body space (55a), and the first to third connection ports (A, B, C) are connected. Are in a fully cooled state where they communicate with each other in the main body space (55a).

    In order to realize such switching, the shape or the like of the through hole (57) is set as follows. That is, the through hole (57) is configured to communicate the first connection port (A) and the second connection port (B) that are adjacent to each other, and has a circular shape in plan view and a constant width. It is formed with. In addition, the through hole (57) has the same circular arc passing through the center in the width direction (hereinafter referred to as the central arc) as the above-described virtual circle that determines the position of the first to third connection ports (A, B, C). The curvature is set concentrically with the virtual circle. The width of the through hole (57) is set to be the same as or slightly larger than the hole diameter of the first to third connection ports (A, B, C).

    On the first and second valve seats (52, 53) side (the upper surface side and the lower surface side in FIG. 2) of the movable valve body (56), a seal groove (56a) extending along the periphery of the through hole (57). Are formed respectively. In the seal groove (56a), a seal ring (66), which is a seal member that closes the gap between the first and second valve seats (52, 53) and the movable valve body (56), is fitted. The seal ring (66) seals the through hole (57) and the internal space (55) so as not to communicate with each other. The seal ring (66) employs a packing made of PTFE (Polytetrafluoroethylene). This PTFE is merely an example, and may be appropriately selected according to usage conditions (fluid pressure or fluid physical properties).

    An O-ring (67) made of an elastic body is provided between the seal ring (66) and the seal groove (56a). The O-ring (67) presses the seal ring (66) toward the first and second valve seats (52, 53).

    The bypass hole (58) opens in the vicinity of the second connection port (B) and on the side opposite to the first connection port (A), and in the cooling state of the flow path switching valve (51), the body space While being in communication with (55a), the flow path switching valve (51) is arranged to communicate with the through hole (57) in the heating state. That is, the bypass hole (58) bypasses the refrigerant from the discharge pipe (11) to the suction pipe (12) in the cooling state, and is closed in the heating state.

-Driving action-
Next, the operation of the air conditioner (1) will be described. In this air conditioner (1), multiple types of operation are possible depending on the setting of each three-way valve (24, 25) and the open / close state of the flow path switching valve (51) of each BS unit (50). ing. Below, typical operation is illustrated and demonstrated among these driving | operations.

<All heating operation>
The all heating operation is for heating each room by all the indoor units (30). As shown in FIGS. 4 and 6, in this operation, the first three-way valve (24) communicates with the second port and the third port, and the second three-way valve (25) communicates with the first port and the second port. Each is set to a state where it communicates with the port. In each BS unit (50), the first and third connection ports (A, C) of the flow path switching valve (51) are in communication with each other, and the second connection port (B) is in a closed state.

    In this operation, a refrigeration cycle is performed in which the outdoor heat exchanger (22) is an evaporator and each indoor heat exchanger (31) is a condenser. In this figure and other figures for explaining other operation operations, dots are attached to the heat exchanger that is a condenser, and the heat exchanger that is an evaporator is illustrated in white. In this refrigeration cycle, the refrigerant discharged from the compressor (21) passes through the second three-way valve (25) and then diverts to each BS unit (50). The refrigerant that has passed through each BS unit (50) is sent to each corresponding indoor unit (30).

    For example, when the refrigerant flows into the first indoor heat exchanger (31) in the first indoor unit (30), the refrigerant radiates heat to the indoor air and condenses in the first indoor heat exchanger (31). . As a result, the room corresponding to the first indoor unit (30) is heated. The refrigerant condensed in the first indoor heat exchanger (31) passes through the first indoor expansion valve (32).

    Here, the opening degree of the first indoor expansion valve (32) is adjusted according to the degree of supercooling of the refrigerant. That is, the first indoor expansion valve (32) increases the flow rate of the refrigerant by increasing the opening degree under the condition that the indoor heating requirement is large and the refrigerant supercooling degree is large, while the heating requirement is small. Under such conditions that the degree of supercooling of the refrigerant is small, the opening degree is reduced to control the flow rate of the refrigerant. In the 2nd and 3rd indoor unit (30), a refrigerant flows like the 1st indoor unit (30), and heating of the corresponding room is performed, respectively.

    The refrigerant that has flowed out of the indoor units (30) joins in the liquid pipe (15). When the refrigerant passes through the outdoor expansion valve (23), the refrigerant is depressurized to a low pressure and flows through the outdoor heat exchanger (22). In the outdoor heat exchanger (22), the refrigerant absorbs heat from the outdoor air and evaporates. The refrigerant evaporated in the outdoor heat exchanger (22) passes through the first three-way valve (24), and then is sucked into the compressor (21) and compressed again.

<All cooling operation>
In the all-cooling operation, all the indoor units (30) cool each room. As shown in FIGS. 5 and 7, in this operation, the first three-way valve (24) communicates with the first port and the second port, and the second three-way valve (25) communicates with the second port and the third port. Set to communicate with the port. Further, in each BS unit (50), the first to third connection ports (A, B, C) are all in communication.

    In this operation, a refrigeration cycle is performed in which the outdoor heat exchanger (22) is a condenser and each indoor heat exchanger (31) is an evaporator. Specifically, the refrigerant discharged from the compressor (21) flows through the outdoor heat exchanger (22) after passing through the first three-way valve (24). In the outdoor heat exchanger (22), the refrigerant dissipates heat to the outdoor air and condenses. The refrigerant condensed in the outdoor heat exchanger (22) passes through the outdoor expansion valve (23) set to a fully opened state, flows through the liquid pipe (15), and is divided into each indoor unit (30).

    For example, in the first indoor unit (30), when the refrigerant passes through the first indoor expansion valve (32), the refrigerant is decompressed to a low pressure and flows through the first indoor heat exchanger (31). In the first indoor heat exchanger (31), the refrigerant absorbs heat from the room air and evaporates. As a result, the indoor cooling corresponding to the first indoor unit (30) is performed.

    Here, the opening degree of the first indoor expansion valve (32) is adjusted according to the degree of superheat of the refrigerant. That is, the first indoor expansion valve (32) increases the flow rate of the refrigerant by increasing the opening degree under the condition that the indoor cooling requirement is large and the degree of superheat of the refrigerant is large, while the cooling requirement is small. In such a condition that the degree of superheat of the refrigerant becomes small, the opening degree is reduced to control the flow rate of the refrigerant. In the second and third indoor units (30), the refrigerant flows similarly to the first indoor unit (30), and the corresponding indoor cooling is performed.

    The refrigerant that has flowed out of each indoor unit (30) flows into the first connection port (A) of each BS unit (50), and then branches and flows to the second and third connection ports (B, C). Here, the refrigerant flowing out from the second connection port (B) is sucked into the compressor (21) after joining. On the other hand, the refrigerant flowing out from the third connection port (C) passes through the second three-way valve (25) after being merged and is sucked into the compressor (21). The refrigerant sucked into the compressor (21) is compressed again.

    Thus, in the all cooling operation, the refrigerant flowing from the indoor heat exchanger (31) into the first connection port (A) of the flow path switching valve (51) is converted into the second and third connection ports (B, C). To be branched. Thereby, the pressure loss of the refrigerant | coolant which flows through the inside of piping can be reduced.

<Simultaneous heating / cooling operation>
In the heating / cooling simultaneous operation, indoor heating is performed in some indoor units, while indoor cooling is performed in other indoor units. In the heating / cooling simultaneous operation, the outdoor heat exchanger (22) serves as an evaporator or a condenser according to the operation conditions. Moreover, in each indoor unit (30), the indoor indoor heat exchanger with a heating request | requirement becomes a condenser, On the other hand, the indoor indoor heat exchanger with a cooling request | requirement becomes an evaporator. Hereinafter, an example of coexistence operation in which the outdoor heat exchanger (22) is a condenser, at least one of the indoor heat exchangers (31) is a condenser, and the rest is an evaporator will be described.

    In the example shown in FIG. 8, the first indoor unit (30) and the second indoor unit (30) heat the room, while the third indoor unit (30) cools the room. As shown in FIG. 8, in this operation, the first and second three-way valves (24, 25) are set in a state in which the first port and the second port are in communication with each other.

    In the first and second BS units (50), the first and third connection ports (A, C) are in communication and the second connection port (B) is in a closed state (see FIG. 4). In the third BS unit (50), the first and second connection ports (A, B) are in communication and the third connection port (C) is in a closed state (see FIG. 3). Here, the third connection port (C) of the third BS unit (50) is not actually completely closed, and is not connected to the third connection port (C) via the bypass hole (58). A small amount of refrigerant flows through the second connection port (B). That is, during the cooling operation, the refrigerant is bypassed from the discharge pipe (11) to the suction pipe (12) through the bypass hole (58). This prevents the refrigerant from condensing in the discharge pipe (11) during the cooling operation.

    In the simultaneous heating / cooling operation, the outdoor heat exchanger (22) and the first and second indoor heat exchangers (31) are used as condensers, while the third indoor heat exchanger (31) is used as an evaporator. A refrigeration cycle is performed. Specifically, the refrigerant discharged from the compressor (21) is divided into the first three-way valve (24) side and the second three-way valve (25) side. The refrigerant that has passed through the first three-way valve (24) is condensed in the outdoor heat exchanger (22), and then flows into the liquid pipe (15) through the outdoor expansion valve (23) adjusted to a predetermined opening degree. To do.

    On the other hand, the refrigerant that has passed through the second three-way valve (25) is divided into the first BS unit (50) side and the second BS unit (50) side. The refrigerant that has flowed out of the first BS unit (50) flows through the first indoor heat exchanger (31). In the first indoor heat exchanger (31), the refrigerant dissipates heat to the indoor air and condenses. As a result, the room corresponding to the first indoor unit (30) is heated. Here, the opening degree of the first indoor expansion valve (32) is adjusted according to the indoor heating request, as in the case of the full heating operation described above. The refrigerant used for indoor heating in the first indoor unit (30) flows out into the liquid pipe (15). Similarly, the refrigerant that has flowed out of the second BS unit (50) is used for room heating in the second indoor unit (30), and then flows out into the liquid pipe (15).

    The refrigerant merged in the liquid pipe (15) flows into the third indoor unit (30). The refrigerant is decompressed to a low pressure when passing through the third indoor expansion valve (32) and then flows through the third indoor heat exchanger (31). In the third indoor heat exchanger (31), the refrigerant absorbs heat from the room air and evaporates. As a result, room cooling corresponding to the third indoor unit (30) is performed. The refrigerant used for cooling the room in the third indoor unit (30) passes through the third BS unit (50), and is then sucked into the compressor (21) and compressed again.

    The above-described simultaneous heating / cooling operation is merely an example. For example, the first indoor unit (30) heats the room while the second and third indoor units (30) cool the room. You may make it.

-Effect of the embodiment-
According to this embodiment, using the flow path switching valve (51) having the valve seat (52) and the movable valve body (56), the movable valve body (56) is rotated around a predetermined axis, Since the communication state between the first to third connection ports (A, B, C) is switched, chattering noise does not occur unlike when a solenoid valve is used. Further, it is not necessary to energize constantly like a solenoid valve, and power saving can be achieved.

    Further, since the communication passage (57) is formed in the movable valve body (56), it is only necessary to seal the periphery of the communication passage (57), and the switching power can be reduced.

    In the cooling state of the flow path switching valve (51), the refrigerant is bypassed from the discharge pipe (11) to the suction pipe (12) via the bypass hole (58). Refrigerant condensation can be suppressed. Further, since only the bypass hole (58) is formed in the first valve seat (52), there is no need to separately provide a bypass pipe, the pipe can be simplified, and the cost can be reduced. .

    Moreover, in the all-cooling state of the flow path switching valve (51) that causes all three indoor heat exchangers (31) to perform a cooling operation, the first heat flow from the indoor heat exchanger (31) to the first flow path switching valve (51). Since the refrigerant flowing into the connection port (A) is branched to the second and third connection ports (B, C), the pressure loss of the refrigerant flowing in the pipe can be reduced.

<< Other Embodiments >>
About each embodiment and each modification mentioned above, it is good also as following structures.

    The number of indoor units and outdoor units described in the above embodiments is merely an example. That is, the air conditioner may be configured by further increasing the number of indoor units and outdoor units.

    As described above, the present invention has a highly practical effect that, in the refrigerant flow switching unit, noise due to self-excited vibration is not generated, and power saving and cost reduction can be achieved. Since it is obtained, it is extremely useful and has high industrial applicability.

10 Refrigerant circuit
11 Discharge pipe
12 Suction tube
21 Compressor
22 Outdoor heat exchanger (heat source side heat exchanger)
25 Second three-way valve (three-way valve)
31 Indoor heat exchanger (use side heat exchanger)
50 BS unit (refrigerant flow path switching unit)
51 Channel switching valve
52 1st valve seat (valve seat)
56 Movable valve body
57 Through hole (communication passage)
58 Bypass hole
A First connection port
B Second connection port
C Third connection port

Claims (6)

Provided in a refrigerant circuit (10) having a compressor (21), a heat source side heat exchanger (22), and a plurality of usage side heat exchangers (31), each usage side heat exchanger (31) being compressed A refrigerant flow path switching unit including a flow path switching valve (51) for switching the flow path of the refrigerant so as to communicate with either the discharge pipe (11) or the suction pipe (12) of the machine (21),
The flow path switching valve (51)
Connected to the first connection port (A) connected to the use side heat exchanger (31), the second connection port (B) connected to the suction pipe (12), and the discharge pipe (11). A third connection port (C) having a valve seat (52) opened in the valve seat surface (52b);
A movable valve element (56) arranged so as to overlap the valve seat (52) and rotatable about a predetermined axis orthogonal to the valve seat surface (52b) of the valve seat (52) has an internal space (55). A cooling state in which the movable valve body (56) is rotated to communicate the first and second connection ports (A, B) and the first and third connection ports (A, C) are communicated with each other. A refrigerant flow path switching unit, comprising: a valve body (54) that switches to a heating state. In claim 1,
The movable valve body (56) includes a communication channel (57) for communicating two adjacent connection ports (A, B) with each other. In claim 2,
The valve body (54) communicates the first and second connection ports (A, B) through the communication passage (57) in the cooling state, while in the heating state, the valve body (54) A refrigerant flow path switching unit configured to communicate the first and third connection ports (A, C) through a main body space (55a) outside the movable valve body (56). In claim 2 or 3,
The refrigerant flow path switching unit, wherein the movable valve body (56) is provided with a seal member (66) that closes a gap with the valve seat (52) at a peripheral edge of the communication path (57). In claim 1,
In the cooling state, the valve seat (52) is connected to the discharge pipe (11) via the body space (55a) outside the movable valve body (56) in the internal space (55) of the valve body (54). ) To the suction pipe (12), a bypass hole (58) for bypassing the refrigerant is formed. In claim 1 or 5,
The refrigerant circuit (10) is connected to a discharge side port connected to the discharge pipe (11), a heat source side port connected to the heat source side heat exchanger (22), and the suction pipe (12). A first three-way valve (24) formed with a suction side port; a discharge side port connected to the discharge pipe (11); a use side port connected to the flow path switching valve (51); and the suction pipe ( A second three-way valve (25) with a suction port connected to 12) is provided,
The valve main body (54) is connected to the internal space of the valve main body (54) in a state in which the use-side port and the suction-side port of the second three-way valve (25) communicate with each other and the discharge-side port is closed. 55) is configured to be switchable to an all-cooling state in which all of the first to third connection ports (A, B, C) are communicated via a main body space (55a) outside the movable valve body (56). A refrigerant flow path switching unit characterized by comprising:

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