JPH0350189B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) This invention relates to a four-way switching valve for a refrigeration system.

(Prior art) In air conditioners for both cooling and heating, a four-way switching valve is interposed in the refrigerant circuit, and the switching operation of the four-way switching valve controls the refrigerant circulation cycle between cooling and heating. Although switching is possible, an example of the specific structure of such a four-way switching valve is the one in the 1980s.
It is described in Publication No. 53825. FIG. 6 shows the overall configuration of the four-way switching valve, and as shown in the figure, the main valve 1 is attached with a pilot solenoid valve
The valve body 102 of No. 01 has first, second, third, and fourth passages 103, 105, 106, and 107. The first passage 13 and the second passage 105 are the discharge pipe 109 and the suction pipe 1 of the compressor 108, respectively.
10, while the third passage 106 and the fourth passage 10
7 is connected to a user side heat exchanger 112 and a heat source side heat exchanger 113, which are connected to each other by a liquid pipe 111. A pressure reducer 135 is installed in the liquid pipe 111. On the other hand, the valve body 1
A substantially bowl-shaped valve body 114 that is slidable in the axial direction is disposed inside the valve body 114.
When located on the right side as shown in the figure, the first passage 103 and the third passage 106 and the second passage 105 and the fourth passage 107 are in communication with each other, whereas when they are located on the left side, the first passage 103 and the third passage 106 are in communication with each other. This allows the four passages 107 and the second passage 105 and third passage 106 to be in communication with each other. Such a valve body 114
In order to move in the axial direction, the valve body 114 has pistons 115 and 1 at both axial ends thereof, respectively.
16 are connected, and these pistons 11
5, 116 and the pilot pressure chamber 1 between each end face.
The valve body 114 is switched by switching between high and low pressure states 17 and 118. In order to switch the pressure state, the pilot solenoid valve 100 is provided, and inside the valve body 121 of the pilot solenoid valve 100 there is an opening approximately at the center of the internal flow path, and a low pressure pipe is connected to the suction pipe 110. Low pressure inlet 123 connected by 122
and first and second passage ports 125 and 126 that open on both sides in the axial direction with the low pressure introduction port 123 in between. In the internal flow path, first and second valve bodies 129 and 130 are arranged, which are connected to each other by a connecting member 131, and these valve bodies 129 and 130 are positioned at the left side as shown in the figure. Then, the first valve body 129 side is opened, the second valve body 130 side is opened, and the first port 125 is connected to the low pressure inlet 1.
23, and on the other hand, when moving to the right,
The first valve body 129 side is closed, the second valve body 130 side is opened, and the second port 126 is connected to the low pressure inlet 123.
communicate with. And the pilot solenoid valve 10
When the electromagnetic coil 132 of No. 0 is energized, it moves to the right side position, while when the electromagnetic coil 132 is not energized, it is moved to the left side by the spring 133. The first port 125 is connected to the main valve 10.
1, and the second port 126 is connected to the right pilot pressure chamber 118 by pilot pipes 119 and 120, respectively. Therefore, when the compressor 108 is driven and high-pressure refrigerant pressure is acting on the discharge piping 109 side and low-pressure refrigerant pressure is acting on the suction piping 110 side, the pilot solenoid valve 100 is turned on (energizing the electromagnetic coil). Then, the second port 12
6 and the low pressure inlet 123 are in communication, and therefore,
The low pressure of the suction pipe 110 is introduced into the right pilot pressure chamber 118, which causes the valve body 11 to
A force is generated that moves 4 to the right. On the other hand, when the pilot solenoid valve 100 is turned off,
At this time, the left pilot pressure chamber 1 of the main valve 101
Low pressure is introduced into 17, which causes the valve body 1 to
14 is switched and moved to the left. By such switching movement of the valve body 114, the utilization side heat exchanger 11
The direction of the refrigerant flowing between the heat exchanger 113 and the heat source side heat exchanger 113 is changed, thereby switching between cooling operation and heating operation.

(Problem to be solved by the invention) As mentioned above, in the four-way switching valve in the conventional device, the power to the pilot solenoid valve is turned ON/OFF.
However, when operating in a refrigerant circulation cycle that requires energization, such as a heating cycle, it is necessary to keep the power energized throughout the operation. It was hot. Also, when heating operation is stopped, the compressor is stopped and
After that, when the power to the pilot solenoid valve is turned off, the pilot solenoid valve returns to the cooling cycle side position due to the spring force, and at this time, a high-low differential pressure state is maintained to some extent in the refrigerant pipe even after the compressor has stopped. Therefore, the main valve is also switched to the cooling cycle side position. At this time, there was a problem in that the high pressure and low pressure were instantaneously mixed within the main valve, resulting in impact noise.

This invention was made in order to solve the above-mentioned conventional problems, and its purpose is to energize the electrical switching means only when switching of the refrigerant circuit is required, and to maintain the state when the electrical switching means is not energized. It is an object of the present invention to provide a four-way switching valve for a refrigeration system, which can save power and extend the life of the coil, and which does not generate switching noise when the operation is stopped.

(Means for solving the problem) Therefore, the four-way switching valve for a refrigerant device of the present invention has the following features:
A discharge pipe 5 and a suction pipe 7 of the compressor 4 are connected to the valve body 3.
first and second passages 6, 8 respectively connected to
and third and fourth passages 9 and 10 respectively connected to the utilization side heat exchanger 12 and the heat source side heat exchanger 14, which are connected to each other by a liquid pipe 16, while the above-mentioned valve body 3, the first to fourth passages 6,
8, 9, and 10, and this channel 1.
Pilot pressure chambers 21 and 22 are provided on both sides in the axial direction with 7 in between.
9 is arranged, and the first passage 6 and the fourth passage 10 and the second passage 8 and the third passage 9 are in communication with each other through the valve body 19, and the first passage 6 is in a first communicating state.
and the third passage 9, and the second passage 8 and the fourth passage 10 are configured to alternately switch the second communication state in which they communicate with each other by axial movement, and each of the pilot pressure chambers 21, 22 includes: The pistons 23 and 24 are respectively disposed so as to be movable in the axial direction, and the valve body 19 and both the pistons 23 and 24 are connected by a connecting member 25, and each of the pilot pressure chambers 21 and 22 is provided with the discharge gas. High-pressure pilot lines 27 and 28 communicate with the piping 5, and low-pressure pilot lines 5 communicate with the suction pipe 7.
7, 58, respectively, and electrical switching means 49, 50 which operate during energization time to one of the high voltage pilot lines 27, 28 and each low voltage pilot line 57, 58, and a fluid resistance to the other. Means 27 and 28 are interposed, respectively, so that the valve body 19 is configured to respond to the pressure difference in the respective pilot pressure chambers 21 and 22.

(Function) In the four-way switching valve for a refrigeration system of the present invention configured as described above, the driving force for switching the valve body 19 is applied to each pilot pressure chamber 21, 22 acting on each piston 23, 24. It is given by the pressure difference. In the following description, for convenience, a case will be described in which electrical switching means 49 and 50 are provided in each of the low voltage pilot lines 57 and 58. When both the electrical switching means 49 and 50 are de-energized, each pilot pressure chamber 21 and 2
2 are both connected to the high-pressure discharge pipe 5 through high-pressure pilot lines 27 and 28, so there is no pressure difference between the pilot pressure chambers 21 and 22, and the valve body 19 remains stationary. do. on the other hand,
When either one of the electrical opening/closing means 49, 50 is energized and opened, the pilot pressure chamber 21 or 22 on the energized side also communicates with the low-pressure suction pipe 7 via the low-pressure pilot line 57 or 58. I will do it. At this time, fluid resistance means 27 and 28 are interposed in the high pressure pilot lines 27 and 28, so that the pressure difference between the discharge pipe 5 and the suction pipe 7 is caused by the fluid resistance means 27 and 28.
or 28, and the pilot pressure chamber 21 or 22 becomes in a low pressure state. This creates a pressure difference between the pilot pressure chambers 21 and 22, and therefore the valve body 19 is switched in the direction of the pressure difference. When the electric opening/closing means 49 or 50 is de-energized after the switching movement, the pilot pressure chamber 21 or 2 which is in a low pressure state
2 returns to its original high pressure state, and therefore the valve body 19
is held in that position. In this way, the valve body 19
Only when the electrical switching means 4 is operated
Switching is performed by selecting valves 9 and 50 and energizing them, and in other non-energized states, the valve body 19
It is possible to perform switching control such that the valve remains in a stationary state, thereby saving power and improving the electrical life of the electrical opening/closing means.Also, switching of the valve body 19 does not occur when the operation is stopped. Therefore, a configuration can be achieved in which no switching noise is generated. In addition, as shown in FIG. 5, the electrical switching means 69,
70 is interposed on each of the high-pressure pilot lines 71 and 72, the same effect can be obtained, although the pressure direction is reversed in the above description.

(Example) Next, a specific example of the four-way switching valve for a refrigeration system according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is an overall configuration diagram showing the four-way switching valve for refrigeration equipment in the first embodiment together with the refrigerant piping system. The valve is composed of a main valve 1 having a refrigerant circulation cycle switching function and a pilot solenoid valve 2 for performing the switching operation.

First, the configuration of the main body 1 will be described. The cylindrical valve main body 3 has a first passage 6 connected to the discharge pipe 5 of the compressor 4 at approximately the center of one side thereof.
Also, a second passage 8 connected to the suction pipe 7 of the compressor 4 is provided approximately at the center of the side surface facing the first passage 6. Also, this second passage 8
Third and fourth passages 9 and 10 are arranged in parallel on both sides in the axial direction, and the third passage 9 is connected to the utilization side exchanger 12 by the first gas pipe 11, and the fourth passage
The passages 10 are each connected to a heat source side heat exchanger 14 by a second gas pipe 13. The utilization heat exchanger 12 and the heat source side exchanger 14 are connected to each other by a liquid pipe 16 in which a pressure reducer 15 constituted by a capillary tube is interposed.
On the other hand, a flow path 17 that communicates the first to fourth passages 6, 8, 9, and 10 is bored in the valve body 3, and the second to fourth passages 6, 8, 9, and 10 are connected to each other. Each opening side of the passages 8, 9, and 10 is formed as a flat valve seat 18, and a valve body 1 is mounted on this flat valve seat 18.
9 is in sliding contact. This valve body 19 has an axial length that can cover two of the openings of the second to fourth passages 8, 9, and 10 arranged in parallel, and has a sliding surface side that is A recess 20 is formed to communicate the two covered openings, and the side opposite to the sliding surface is formed as a curved surface along the recess 20 and is spaced apart from the opening of the first passage 6. Therefore, when the valve body 19 is located on the left side as shown in FIG. 1, a first communication state is established in which the first passage 6 and the fourth passage 10 and the second passage 8 and the third passage 9 are in communication with each other. On the other hand, when it is located on the right side of the figure, a second communication state is provided in which the first passage 6 and the third passage 9 and the second passage 8 and the fourth passage 10 are in communication with each other.

Further, within the valve body 3, pilot pressure chambers 21 and 22 are provided on both sides in the axial direction with the flow path 17 in between, and these pilot pressure chambers 2
1 and 22, there is a piston 2 movable in the axial direction.
3 and 24 are arranged, respectively. These pistons 23 and 24 and the valve body 19 are connected by a connecting member 25. Therefore, when there is a difference in pressure between the pilot pressure chambers 21 and 22, the force due to the pressure difference acts on the pistons 23 and 24, for example, as shown in FIG.
When the pilot pressure chamber 21 on the left side becomes higher than the pilot pressure chamber 22 on the right side, the valve body 19 is moved to the right side together with both pistons 23 and 24, thereby changing the state from the first communication state. ,
A switch to the second communication state is made. Note that each of the pistons 23 and 24 has the flow path 1.
Throttle holes 27 and 28 are formed to communicate between the pilot pressure chambers 21 and 22, respectively, and the end plates 29 and 30 that cover each end of the pilot pressure chambers 21 and 22 are provided with Pilot ports 31 and 32 are provided which open into each of the pilot pressure chambers 21 and 22, respectively.

Next, the configuration of the pilot solenoid valve 2 will be described. A pilot flow path 41 bored in the axial direction of the pilot valve body 40 includes a low pressure inlet 4.
2, and a first port 43 and a second port 44 are bored on both sides of the low pressure inlet 42 in the axial direction. The first valve seat 45 is located between the first port 43 and the first valve seat 45.
However, a second valve seat 46 is formed between the low pressure inlet 42 and the second port 44, respectively. Pilot valve bodies 47 and 48 which can be moved into and out of contact with the first and second valve seats 45 and 46 are arranged respectively, and these pilot valve bodies 47 and 48 each operate a solenoid valve unit 49 which serves as an electrical opening/closing means. ，
50, each electromagnetic coil 51, 52
The valve is opened by energizing the valve, and the valve is closed by the spring force of the return springs 53 and 54 by stopping the energization. The low pressure inlet 42 of the pilot solenoid valve 2 is connected to the suction pipe 7 through a low pressure pipe 55, and the first port 43 and second port 44 are connected to the pilot ports 31 and 32 of the main valve 1 for low pressure. pilot line 5
7 and 58, respectively.

The operating state of the first embodiment configured as described above will now be described. First, as shown in FIG. 1, the valve body 19 of the main valve 1 is on the left side, that is, in the first communication state position, and both the electromagnetic coils 51 and 52 of the pilot electromagnetic valve 2 are not energized.
The operation of the compressor 4 is started. At this time, the refrigerant discharged from the compressor 4 circulates in the direction of the solid arrow in the figure and returns to the compressor 4, and the user-side heat exchanger 12 acts as an evaporator and absorbs heat from the outside. A refrigerant circulation cycle is formed as a cooling operation. At this time, each pilot pressure chamber 2 of the main valve 1
1 and 22, the high pressure of the high pressure gas refrigerant discharged from the compressor 1 and flowing into the flow path 17 through the discharge pipe 5 and the first passage 6 is through throttle holes 27 and 28 provided in each piston 23 and 24. acts through.
On the other hand, each low pressure pilot line 57, 58 connected to each pilot pressure chamber 21, 22 is
is each pilot valve body 4 of the pilot solenoid valve 2.
7, 48, and therefore each pilot pressure chamber 21, 22 is connected to the flow path 1.
In this state where there is no pressure difference, no force is generated to move the valve body 19 in the axial direction, and this state is maintained, so that cooling operation is not performed. It will be continued.

On the other hand, while the compressor 4 is operating, the pilot solenoid valve 2
When the right electromagnetic coil 52 is energized, the right pilot valve body 48 separates from the second valve seat 46,
This allows the low pressure inlet 42 and the second port 44 to
Therefore, the pilot pressure chamber 22 on the right side communicates with the suction pipe 7 which is in a low pressure state through the low pressure pilot pipe 58 and the low pressure pipe 55.
Therefore, the refrigerant flows from the high pressure passage 17 to the low pressure suction pipe 7 via the pilot pressure chamber 22 on the right side, but there is a flow between the high pressure passage 17 and the pilot pressure chamber 22 on the right side. Since the fluid resistance of the throttle hole 28 is present, a pressure drop occurs in the throttle hole 28, and the right pilot pressure chamber 22 becomes under pressure. In this manner, the throttle holes 27 and 28 provided in each piston 23 and 24 serve both as a fluid resistance means and as a high-pressure pilot line in this embodiment. From the above, a pressure difference is generated between the pilot pressure chambers 21 and 22, and the force acting on each piston 23 and 24 due to the pressure difference causes the pistons to move together with the valve body 19 to the right in the direction of the pressure difference. It is. Then, the shaft end of the right piston 24 is moved to a position where it abuts the end plate 30, and the accompanying movement of the valve body 19 switches to the second communicating state. At this time, the refrigerant flowing in from the discharge pipe 5 will circulate in the direction of the dashed arrow in the figure, and the user-side heat exchanger 12 will be used as a condenser to radiate heat to the outside, forming a heating operation cycle. . In this way, when the power supply to the right electromagnetic coil 52 is stopped after the cycle switching is completed, the communication state of the right pilot pressure chamber 22 to the low pressure is canceled, and the inside of the flow path 17 is the same as the beginning. Although the pressure returns to the same high pressure state as above, after this, no differential pressure that moves the valve body 19 in the axial direction occurs, so that the heating operation described above can be continued.

As explained above, in the conventional device, it was necessary to constantly energize the pilot solenoid valve during either cooling or heating operation, but in the above embodiment, it was necessary to switch the refrigerant circulation cycle. Only occasionally can the switching be accomplished by selectively energizing the electromagnetic coil for the time required for the axial movement of the valve body 19. In addition, in conventional equipment, when the power supply to the pilot solenoid valve is stopped almost at the same time as the compressor is stopped, the position of the valve body is also changed, and at this time, the high-pressure refrigerant and low-pressure refrigerant are instantaneously mixed. However, in the above embodiment, since the valve body 19 does not move after the compressor 4 is stopped, the above-mentioned impact noise is not generated.

FIG. 2 is an operating circuit diagram of the above embodiment,
The circuit is configured to generate a switching signal every time the compressor 4 is started. Therefore, when the same operation as the previous operation cycle is carried out, a switching signal is generated, but no movement occurs because the valve body 19 is already in the selected switching position.
In FIG. 2, a compressor drive relay R1 is connected to a first connection wiring L1 of power lines A and B via a manual cooling/heating switch S1 and a temperature detection switch S2 of a temperature controller. When the cooling side is selected with the cooling/heating selector switch S1,
When the temperature detection switch S2 is in the H side operation (when the room temperature is higher than the set temperature), the compressor drive relay R1 is turned on and the compressor 4 is operated. Also, when the heating side is selected with the cooling/heating selector switch S1, the temperature detection switch S2 is set to H.
In side operation, compressor drive relay R1 is turned OFF.
The normally open contact R1-1 of this compressor drive relay R1 is interposed in the energization control wiring L2, L3 of the electromagnetic coil, that is, the wiring L2 is connected to the cooling side of the cooling/heating changeover switch S1 of the dual configuration. The left electromagnetic coil 51 of the pilot electromagnetic valve 2 is connected to the terminal via the normally closed contact TM1-1 of the timer TM1. Therefore, when the switch S1 is selected to the cooling side, the compressor drive Relay R1
Each time it is turned on, the electromagnetic coil 51 starts to be energized, and after the time elapses, the timer TM1, which is set in anticipation of the switching movement time of the valve body 19, is turned on and the contact TM1-1 is turned on. This opens the electromagnetic coil 51 and stops energizing the electromagnetic coil 51. In the wiring L3 with a similar configuration, when the heating side is selected, the compressor drive relay R1 turns ON, then the timer TM2 turns ON, and its normally closed contact TM2-2 opens. Until then, the right electromagnetic coil 52 is energized. The connection wiring L4 is the control wiring during defrost operation,
Heat source side heat exchanger 1 placed outdoors during heating operation
When the amount of frost buildup increases and it becomes necessary to remove it, the frost amount detection switch S3 in the defrost control circuit DF closes, which causes the auxiliary relay R2 to close.
ON operates. Normally closed contact R2 of this auxiliary relay R2
-1 is opened, the wiring L3 side is cut off from the power line A, and the normally open contact R2-2 of the auxiliary relay R2 is closed, the power line A and the wiring L are closed.
The second side becomes conductive, and the left electromagnetic coil 51 is energized for the time set by timer TM1 in the same way as described above.
The main valve 1 is switched to the cooling cycle position, and defrost operation is performed in this position.

FIG. 3 shows an operating circuit having the same functions as those in FIG. 2, and the same parts are denoted by the same numbers and the explanation thereof will be omitted. In the operating circuit shown in Figure 3, wiring L2 and L3
In this case, positive characteristic thermistors PTC1 and PTC2 are used in place of the timers TM1 and TM2 in FIG. 2, respectively. These positive characteristic thermistors
PTC1 and PTC2 are elements whose resistance value increases as the temperature rises due to self-heating due to energization. Therefore, initially they have low resistance, current flows, and as time passes, the resistance increases and the current The function of the timer is substituted by using the resistance-time characteristic that interrupts the time.

Next, the second part of the four-way switching valve for refrigeration equipment of the present invention will be described.
An example of this will be described with reference to FIG. In this embodiment, the configuration of the main valve 1a is substantially the same as that of the main valve 1 of the first embodiment, and therefore, the same functional parts are denoted by the same numbers with the suffix a, and the explanation thereof will be omitted. In this main valve 1a, the first
The difference from the embodiment is that each piston 27a, 28a
No throttle hole is provided in the pilot pressure chambers 21a and 21b, so the pressure in each pilot pressure chamber 21a and 21b is separated from the pressure on the flow path 17a side by each of the pistons 27a and 28a. Each of the pilot pressure chambers 21a and 22a is connected to the discharge pipe 5a by high-pressure pilot lines 63 and 64 in which fluid resistance means 61 and 62 such as capillary tubes are interposed, respectively.
It is connected to the suction pipe 7a by low-pressure pilot lines 67, 68 in which electromagnetic valves 65, 66 which are opened when energized are interposed. In the above configuration, when both the solenoid valves 65, 66 are not energized, the pressure of the high pressure gas refrigerant discharged from the compressor 4a is transferred to each pilot pressure chamber 21a, 22a from the discharge pipe 5a. pilot line 63,
64, and the pressure difference therebetween is the same in both high-pressure states, so the valve body 19a remains in its current state. On the other hand, only when one of the solenoid valves 65 and 66, for example, the right solenoid valve 66, is energized to open, the right pilot pressure chamber 2
2a communicates with the suction pipe 7a via the low-pressure pilot line 68 and is brought into a low-pressure state, thereby creating a pressure difference between both pilot pressure chambers 21a and 22a and generating a force that moves the valve body 19a to the right. It is. Therefore, in the second embodiment, as in the first embodiment, only when it is necessary to switch the communication state of the main valve 1a, the switching can be performed by energizing a predetermined solenoid valve. can.

Next, FIG. 5 shows a third embodiment.
The structure of the main valve 1b in this embodiment is the same as that in the second embodiment, and is designated by the same number with the suffix b, and the explanation thereof will be omitted. In the third embodiment,
Each pilot pressure chamber 21b, 22b is connected to the discharge piping 5b by a high-pressure pilot line 71, 72, which is provided with a solenoid valve 69, 70 that opens when energized, and is composed of a capillary tube or the like. It is connected to the suction pipe 7b by low pressure pilot lines 75, 76 in which fluid resistance means 73, 74 are interposed. Therefore, when both the solenoid valves 69 and 70 are not energized, the suction pipe 7 is connected to each pilot pressure chamber 21b and 22b.
The same low pressure at b acts on the valve body 19a.
On the other hand, when either of the solenoid valves 69, 70 is energized, the high pressure in the discharge pipe 5b is introduced into the pilot pressure chamber 21b or 22b on the energized side, and both pilot pressure chambers 21b, 22b is generated, and the switching movement of the valve body 19b is performed.

As explained above, in each of the above embodiments, the electrical switching means is selected only when switching operation is required, and the switching operation is performed by energizing for a short time necessary for switching operation. Furthermore, since the current position is maintained even when the current is cut off, power consumption can be reduced, and there is almost no rise in temperature of the coil, improving durability.
Furthermore, it becomes possible to use a coil with a single hour rating, which also allows for miniaturization. In addition, there is no switching action in the main valve even when the operation is stopped, so
There is no switching noise.

(Effects of the Invention) As explained above, in the four-way switching valve for refrigeration equipment of the present invention, electrical switching is performed only when switching of the refrigerant circulation cycle is necessary, and only for a short period of time required for switching movement of the valve body. By energizing the means,
Furthermore, since the stationary position after movement is maintained after the power supply is stopped, it is possible to save power and improve the electrical life of the electrical switching means, as well as reduce the switching noise when the operation is stopped. Occurrence can be prevented.

[Brief explanation of drawings]

FIG. 1 is a refrigerant circuit diagram including a partial cross section showing the overall configuration of a first embodiment of the present invention, FIG. 2 is an operating circuit diagram of the device shown in FIG. 1, and FIG. 3 is a configuration different from that in FIG. 2. Fig. 4 is a refrigerant circuit diagram showing the overall configuration of the second embodiment, Fig. 5 is a refrigerant circuit diagram showing the overall configuration of the third embodiment, and Fig. 6 shows the four main paths of a conventional refrigeration system. FIG. 2 is a refrigerant circuit diagram showing the overall configuration of a switching valve. 3...Valve body, 4...Compressor, 5...Discharge piping, 6...First passage, 7...Suction piping, 8...Second passage, 9...Third passage, 10...Fourth passage passage, 1
2... User side heat exchanger, 14... Heat source side heat exchanger, 16... Liquid pipe, 17... Channel, 19... Valve body, 21, 22... Pilot pressure chamber, 23, 2
4... Piston, 25... Connection member, 27, 28
... Throttle hole (high pressure pilot line) (fluid resistance means), 49, 50 ... Solenoid valve unit (electrical opening/closing means), 57, 58 ... Low pressure pilot line.

Claims (1)

[Claims] 1 First and second passages 6, 8 connected to the discharge pipe 5 and suction pipe 7 of the compressor 4, respectively, and a user-side heat exchanger 12 connected to each other by a liquid pipe 16 in the valve body 3. and third and fourth passages 9 and 10 connected to the heat source side heat exchanger 14, respectively.
A flow path 17 that communicates the passages 6, 8, 9, and 10, and pilot pressure chambers 21 and 22 are provided on both sides of the flow path 17 in the axial direction, respectively, and a valve body 19 is disposed within the flow path 17. , with this valve body 19, the first
A first communication state in which the passage 6 and the fourth passage 10, and the second passage 8 and the third passage 9 communicate with each other, and a first communication state in which the first passage 6 and the third passage 9, and the second passage 8 and the fourth passage 10 The second communication state in which they communicate with each other is alternately switched by axial movement, and pistons 23 and 24 are respectively arranged in the pilot pressure chambers 21 and 22 so as to be movable in the axial direction, and the valves are connected to each other. body 19 and both pistons 23,
24 are connected by a connecting member 25, and each of the pilot pressure chambers 21, 22 is connected to a high pressure pilot line 27, 28 communicating with the discharge pipe 5.
and low-pressure pilot lines 57, 58 communicating with the suction pipe 7, respectively, and an electric circuit that opens when energized either one of the high-pressure pilot lines 27, 28 or the low-pressure pilot lines 57, 58. The target opening/closing means 49, 50 are interposed on the other side, and the fluid resistance means 27, 28 are interposed on the other side, respectively.
The valve body 19 is connected to each of the pilot pressure chambers 21 and 2.
1. A four-way switching valve for a refrigeration system, characterized in that it is configured to respond to a pressure difference between two points.