JPH0378548B2 - - Google Patents

Description

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

(Prior art) In an air conditioner for both cooling and heating, a four-way switching valve is installed in the refrigerant circuit, and the switching operation of this four-way switching valve controls the refrigerant circulation cycle between cooling and heating. Although it is said that switching is possible,
JP-A-53825 discloses an example of a specific structure of a pilot type four-way switching valve for a refrigeration system in which a pilot solenoid valve is attached to a main valve. FIG. 3 shows the overall configuration of the four-way switching valve, and as shown in the figure, the valve body 102 of the main valve 101 is connected to
07. The first passage 103 and the second passage 105 are the discharge piping 1 of the compressor 108, respectively.
09 and the suction pipe 110, while the third passage 10
6 and the fourth passage 107 are respectively connected to a utilization 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, a substantially bowl-shaped valve body 114 that is slidable in the axial direction is disposed within the valve body 102, and when the valve body 114 is located at the right position as shown in the figure, the first passage 103 and the third passage 106, and when the second passage 105 and the fourth passage 107 are located on the left side, the first passage 103 and the fourth passage 107, and the second passage 105 and the third passage 106 are in communication with each other. Communication can be obtained for each. In order to perform such axial switching movement of the valve body 114, pistons 115 and 116 are connected to both ends of the valve body 114 in the axial direction. By switching the high and low pressure states of the pilot pressure chambers 117 and 118 between them, the valve body 114 is switched and moved. In order to switch the pressure state, a pilot solenoid valve 100 is provided, and a valve body 12 of this pilot solenoid valve 100
1 includes a low pressure inlet 123 connected to the suction pipe 110 by a low pressure pipe 122, and first and second ports 125, 12 with this low pressure inlet 123 in between.
6 is drilled. A pilot valve body 129 having two valve parts 129a and 129b is disposed inside the pilot valve body 129.
However, without energizing the electromagnetic coil 132, the spring 133
Therefore, when the valve is located in the left position as shown in the figure, the valve part 129a side is opened and the valve part 129b side is closed, and the first port 125 is connected to the low pressure inlet 123.
On the other hand, when the electricity is applied and it moves to the right side, the valve part 129a side is closed and the valve part 129b side is opened, and the second communication port 126 is connected to the low pressure inlet 123.
communicate with. The first port 125 is connected to the left pilot pressure chamber 117 of the main valve 101, and the second port 126 is connected to the right pilot pressure chamber 118.
They are connected to each other by pilot pipes 119 and 120, respectively. Therefore, the compressor 108
is driven, and high pressure refrigerant pressure is applied to the discharge pipe 109 side.
On the other hand, when the electromagnetic coil 132 is energized while low pressure refrigerant pressure is acting on the suction pipe 110 side, the low pressure of the suction pipe 110 is introduced into the right pilot pressure chamber 118, thereby causing the valve body 114 to move to the right side. A force is generated to move the object.
On the other hand, when the pilot solenoid valve 100 is turned off, low pressure is introduced into the left pilot pressure chamber 117, thereby switching the valve body 114 to the left. By such switching movement of the valve body 114, the direction of the refrigerant flowing through the user-side heat exchanger 112 and the heat source-side heat exchanger 113 is switched, thereby switching between cooling operation and heating operation. will be done.

(Problems to be Solved by the Invention) As mentioned above, in the four-way switching valve of the conventional device, when operating in a refrigerant circulation cycle that requires energization of the pilot solenoid valve, for example, a heating cycle, It was necessary to keep the power on during operation. In addition, when the compressor is stopped when heating operation is stopped, and then the power to the pilot solenoid valve is turned off, the pilot solenoid valve is moved to the cooling cycle side position by the spring force, and at this time there is no compressor in the refrigerant pipe. Since the differential pressure state is maintained to some extent even after the machine is stopped, the main valve is also switched to the cooling cycle side position. At this time, there was a problem in that the high pressure side and the low pressure side 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 when switching to the refrigerant circulation cycle on the side that requires energization of the pilot solenoid valve is required. The pilot solenoid valve is energized for a short period of time only when the pilot solenoid valve is energized, and maintains its state when it is de-energized.Therefore, it saves power and extends the life of the coil, and does not produce switching noise when the operation is stopped. An object of the present invention is to provide a road switching valve.

(Means for Solving the Problems) Therefore, the pilot type four-way switching valve for a refrigeration system of the present invention is designed to improve communication between a pair of passages 6 and 8 and another pair of passages 9 and 10. The main valve 1 can be switched between high and low pressures in two pilot pressure chambers 21 and 22, the low pressure generating section 7 in the refrigerant circuit accompanying the operation of the compressor 4, and each pilot pressure chamber 21 of the main valve 1. , 22, the pilot valve main body 40 of the pilot solenoid valve 2 is connected to the low pressure generating section 7 in the refrigerant circuit. First port 42 to be connected
and second and third ports 43 and 44 connected to the pilot pressure chambers 21 and 22, respectively, and a pilot valve body 49 is disposed within the pilot valve main body 40. body 4
When moving due to the energization of 9, the third
The communication port 44 is configured to communicate with the second communication port 43, and the second communication port 43 is configured to be switched to communicate with the first communication port 42 when the urging means 52 returns from the energized state, and the communication state of the main valve 1 is changed. When a high-low pressure difference greater than the value required for switching occurs in the refrigerant circuit, the first port 4 acts on the pilot valve body 49 located on the side of movement due to the energization.
The configuration is such that the resultant force of the force in the return direction due to the refrigerant pressure on the second side and the force in the movement direction due to the refrigerant pressure on the second port 43 side is larger than the return force due to the biasing means 52. There is.

(Function) In the pilot type four-way switching valve for a refrigerant device of the present invention configured as described above, for example, the device is configured such that it is necessary to energize the pilot solenoid valve 2 on the refrigerant circulation cycle side during cooling. To explain this, when the pilot solenoid valve 2 is energized, the pilot valve body 49 moves to the side where the first port 42 and the third port 44 communicate with each other, and at this time, the compressor 4
When the main valve 1 is operated and a high-low pressure difference occurs in the refrigerant circuit, the pilot pressure chambers 21, 22 of the main valve 1 will The above-mentioned high pressure and low pressure act on the main valve 1, and the communication state within the main valve 1 is changed according to the pressure state, for example, switching to provide a cooling cycle is performed. After that, when the energization to the pilot solenoid valve 2 is stopped and the electromagnetic force applied to the pilot valve body 9 is released, the return force from the urging means 52 is applied to the pilot valve body 49 as well as the return force from each of the ports 42, 4.
Although the refrigerant pressure introduced into the ports 3 and 44 is acting, the force due to the refrigerant pressure on the second port 43 side (the force acting in the moving direction due to energization) is
The force (force acting in the return direction) due to the refrigerant pressure on the first port 42 side communicating with 4 and the urging means 5
2, the pilot valve body 49 is held at that position without returning. Therefore, each pilot pressure chamber 2 of the main valve 1
The high and low pressure states at 1 and 22 are maintained as they are, no switching of the communication state occurs, and the cooling operation continues. Then, the compressor 4 is stopped and the pressure difference in the refrigerant circuit gradually decreases, and the force due to the refrigerant pressure acting on the pilot valve body 49 decreases, becoming smaller than the return force of the urging means 52. When the valve is completely discharged, the pilot valve body 49 is returned to the de-energized side. However, since the refrigerant pressure state at this time is smaller than the value required to switch the communication state of the main valve 1, even if the high and low pressure states of each pilot pressure chamber 21 and 22 of the main valve 1 are switched, Switching of the communication state within the main valve 1 does not occur. With such a switching operation state, in the above example, the refrigerant cycle can be switched by energizing the compressor 4 for a short time only when starting cooling operation, and thereafter there is no need to energize. This makes it possible to save power and improve the life of the coil, and since the communication state of the main valve 1 does not change even when the operation is stopped, no switching noise is generated.

(Embodiments) Next, specific embodiments of the pilot type four-way switching valve for refrigeration equipment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an overall configuration diagram showing a pilot type four-way switching valve for a refrigeration system together with a refrigerant piping system according to an embodiment of the present invention. It consists of a main valve 1 having a circulation cycle switching function and a pilot solenoid valve 2 for performing the switching operation.

First, the structure of the main valve 1 will be described. The cylindrical valve body 3 has a pair of first and second passages 6 and 8 located approximately at the center of opposing sides, and the second passage 8. Third and fourth passages 9 and 10 forming another pair are provided on both sides of the passage in the axial direction, and the first passage 6 is connected to the discharge pipe 5 of the compressor 4.
Further, the second passage 8 is connected to the suction pipe 7, the third passage 9 and the fourth passage 10 are connected to the heat source side heat exchanger 12 and the usage side heat exchanger 14, and the first gas pipe 11 and the second gas pipe 13 and are connected to each other. The heat source side heat exchanger 12 and the usage side heat exchanger 14 are:
Pressure reducer 15 composed of a capillary tube
are connected to each other by a liquid pipe 16 interposed therebetween. On the other hand, inside the valve body 3, the first to fourth
A channel 17 is bored through which the channels 6, 8, 9, and 10 communicate with each other, and the second to fourth channels enter into this channel 17.
Each opening side of the passages 8, 9, 10 is provided with a flat valve seat 18.
A valve body 19 is in sliding contact with the flat valve seat 18. 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, so that the valve body 19 is located on the right side as shown in FIG. When located in the first passage 6 and the third passage
On the other hand, when the first passage state where the passage 9, the second passage 8 and the fourth passage 10 are in communication with each other is located at a position on the left side of the figure, the first passage 6 and the fourth passage 1 are in communication with each other.
0, and a second communication state in which the second passage 8 and the third passage 9 are in communication with each other is provided.

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
Pistons 23 and 24 having substantially the same diameter are disposed within the pistons 1 and 22 so as to be movable in the axial direction. These pistons 23 and 24 and the valve body 19
are connected to each other 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, and for example, in FIG. 22 becomes higher than the pilot pressure chamber 21 on the left side, the valve body 19 is moved to the left side together with both pistons 23 and 24, thereby changing the state from the first communicating state to the second communicating state. The switch is made to . Each of the pistons 23 and 24 is provided with throttle holes 27 and 28, respectively, which communicate the flow path 17 side and each pilot pressure chamber 21 and 22 side, and each pilot pressure chamber 21 and 22 Pilot ports 31, 32 are provided in end plates 29, 30 that cover each end of the pilot pressure chambers 21, 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 has a first port 42.
and second ports on both sides of the first port 42 in the axial direction.
A port 43 and a third port 44 are bored,
In the pilot flow path 41, the first port 4 is provided.
A first valve seat 45 is formed between the valve 2 and the second port 43, and a second valve seat 46 is formed between the first port 42 and the third port 44, respectively. and first and second valve seats that can approach and separate from the first and second valve seats 45 and 46;
A pilot valve body 49 having valve parts 47, 48 is arranged. This pilot valve body 49 is connected to a solenoid valve unit 50, and the solenoid coil 5
1, the pilot valve body 49 is moved to the right, and the first valve portion 47 is moved to the first valve seat 45.
The second valve portion 48 is in contact with the second valve seat 46 .
This causes the third port to enter the first port 42.
A communication state in which the port 44 communicates is obtained. on the other hand,
When the electromagnetic coil 51 is de-energized, the pilot valve body 49 returns to the left side from the position shown in the drawing by the spring force of the return spring 52 provided as a biasing means. In this position, the first valve portion 47 is separated from the first valve seat 45 so that the second port 43 communicates with the first port 42, and the second valve portion 48 is in contact with the second valve seat 46. , the third port 44 is blocked from the first port 42. The first port 42 is connected to the suction pipe 7 through a low pressure pipe 55, and the second port 43 and the third port 44 are connected to the pilot port 31, 32 of the main valve 1 through the pilot pipe 5.
7 and 58, respectively.

When the main valve 1 and the pilot solenoid valve 2 are connected in this way, the following return movement can be achieved depending on the diameter of the first valve seat 45 in the pilot solenoid valve 2 and the spring force of the return spring 52. It is made so that it can be done. That is, when the electromagnetic coil 51 is energized and the pilot valve body 49 is moving to the right, pressure is generated in the pilot flow path 41 at the first valve seat 45 where the first valve portion 47 is in contact. On the second port 43 side, the pressure of the high-pressure refrigerant discharged from the compressor 4 flows through the throttle hole 27 of the left piston 23 in the main valve 1, the left pilot pressure chamber 21, and the left pilot piping 57, respectively. On the other hand, the third port 4
On the first port 42 side communicating with 4, the low pressure pipe 55
The pressure is approximately equal to the pressure of the suction pipe 7, which is in a low pressure state via. From the above, the pilot valve body 49 has a pressure equal to the product of the differential pressure between the high pressure on the second port 43 side and the low pressure on the first port 42 side, and the aperture area of the first valve seat 45. This force acts on the first valve seat 45 in the valve closing direction. If the return spring 52 does not have a spring force exceeding this valve-closing force, the pilot valve body 49 will not return even if the electromagnetic coil 51 is de-energized. Therefore, in this embodiment, the compressor 4 is stopped and the pressure difference between the high pressure refrigerant pressure on the discharge pipe 5 side and the low pressure refrigerant pressure on the suction pipe 7 side gradually decreases.
In the process, each pilot pressure chamber 2 of the main valve 1
When the differential pressure becomes smaller than the value at which switching movement of the valve element 19 cannot be achieved even if the high and low pressure states of 1 and 22 are switched, the pilot valve element 49 detects the difference that has similarly decreased in the pilot flow path 41. The spring force of the return spring 52 overcomes the valve-closing force caused by the pressure and causes the return movement. 5
Reference numeral 3 designates an adjustment spring for adjusting the return operating state. Note that, as shown in FIG. 1, a defrost bypass pipe 61 in which a defrost solenoid valve 60 is interposed is connected to the discharge pipe 5 of the compressor 4 and the liquid pipe 16.

The operating state of the above-described 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 right side, that is, the
The solenoid coil 51 of the pilot solenoid valve 2 is energized and the compressor 4 starts operating. At this time, the refrigerant discharged from the compressor 4 circulates in the direction of the solid line arrow in the figure and returns to the compressor 4.
The user-side heat exchanger 14 acts as an evaporator and absorbs heat from the outside, thus forming a refrigerant circulation cycle for cooling operation. At this time, main valve 1
Each pilot pressure chamber 21, 22 is equipped with a compressor 1.
The high pressure of the high-pressure gas refrigerant that is discharged from the piston 5 and flows into the flow path 17 through the discharge pipe 5 and the first passage 6 is transmitted through the throttle hole 27 provided in each piston 23 and 24.
Acts through 28. On the other hand, the pilot piping 5 connected to the left pilot pressure chamber 21
7 is a pilot valve body 49 of the pilot solenoid valve 2
The flow passage is blocked by the first valve portion 47 of the left pilot pressure chamber 21.
is maintained at the same pressure as the high pressure in the flow path 17. On the other hand, the second valve body 48 is separated from the second valve seat 46, which causes the first passage 42 and the third
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 pilot pipe 58 and the low pressure pipe 55 on the right side. 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 fluid resistance exists due to the throttle hole 28, a pressure drop occurs in the throttle hole 28, and the right pilot pressure chamber 22 is therefore in a low pressure state. From the above, there is a pressure difference between both pilot pressure chambers 21 and 22,
This acts on each piston 23, 24, respectively,
This urges the valve body 19 to the right in the direction of the differential pressure. If the power supply to the pilot solenoid valve 2 is stopped and the electromagnetic force that was attracting the pilot valve body 49 to the right side is released, the pilot valve body 49 will have a
In addition to the spring force exerted in the leftward direction by the return spring 52, the pressure of the refrigerant introduced into the pilot flow path 41 acts. As described above, the acting force of this refrigerant during steady operation of the compressor 4 is greater than the return force of the return spring 52, so even after the electromagnetic coil 51 is de-energized, the pilot valve body 49 does not switch. Therefore, cooling operation can be continued.

Next, the operating state when the compressor 4 is stopped from the above operating state will be explained. When the compressor 4 is stopped, the high and low pressures that had been occurring in the refrigerant piping will be gradually equalized over time, and the differential pressure will become smaller. When the return force of the return spring 52 becomes greater than the force acting on the pilot valve element 49, the pilot valve element 49 is moved back and the communication state of each of the ports 42, 43, 44 is switched. However, as described above, even if the high and low pressure states in the pilot pressure chambers 21 and 22 of the main valve 1 are switched at this time, the valve element 19 is constructed so as not to be moved in the axial direction at that differential pressure value. Therefore, the communication state before the stop is maintained in the main valve 1 even after the main valve 1 is stopped. Therefore, when restarting with the same cooling operation as the previous operation cycle, when the compressor 4 is started, the pilot solenoid valve 2 is energized, the pilot solenoid valve 49 is moved to the right, and a predetermined differential pressure condition is established in the refrigerant pipe. It is necessary to continue the above-mentioned energization for a short period of time until a It does not occur through cessation.

In addition, when switching to the heating cycle at the beginning of the heating season, by starting the compressor 4 without energizing the pilot solenoid valve 2, the pressure inside the main valve 1 is activated during the generation of the differential pressure in the refrigerant pipe. The communication state is switched, and heating operation is performed in a refrigerant circulation cycle shown in the direction of the broken line arrow in FIG. After that, start up without energizing pilot solenoid valve 2.
By operating and stopping, the communication state on the cooling cycle side is maintained. In addition, if frost forms on the heat source side heat exchanger 12 placed outdoors during heating operation, and this defrosting operation becomes necessary and a defrost command is generated, the above-mentioned heating refrigerant circulation cycle is continued. In this state, the defrost solenoid valve 60 shown in FIG.
Defrost operation is performed.

FIG. 2 is an operating circuit diagram of the above embodiment. In the figure, the power supply lines A and B include a compressor drive relay R1 connected to the first connection wiring L1, a manual cooling/heating switch S1, and a temperature controller. is connected to the temperature detection switch S2, and when the cooling side is selected with the cooling/heating changeover switch S1, the compression The machine drive relay R1 is turned on and the compressor 4 is operated. Further, when the heating side is selected by the cooling/heating changeover switch S1, the compressor drive relay R1 is turned OFF when the temperature detection switch S2 is operated on the H side. The normally open contact R1-1 of this compressor drive relay R1 is interposed in the energization control wiring 12 of the electromagnetic coil, that is, in the wiring L2, it is connected to the cooling side terminal of the cooling/heating changeover switch S1 of the dual configuration. The solenoid coil 51 of the pilot solenoid valve 2 is a timer TM.
Therefore, when the switch S1 is selected to the cooling side, the electromagnetic coil 51 is energized every time the compressor drive relay R1 is turned on. started, and
A timer TM whose timer is set in anticipation of the time it takes for the pilot valve body to move due to electromagnetic force and for the difference in pressure between high and low levels to occur in the refrigerant piping, which causes the position of the pilot valve to be maintained even if the energization is stopped. After that time has passed, the contact TM turns ON.
-1 is opened, and the energization to the electromagnetic coil 51 is stopped. The connection wiring L3 is a control wiring during defrost operation, and the frost amount detection switch S3 in the defrost control circuit DF is closed, thereby energizing the defrost solenoid valve 60, which is opened. Defrost operation as described above is performed.

As explained above, in the conventional device, it is necessary to constantly energize the pilot solenoid valve during either cooling or heating operation, but in the above embodiment, the pilot solenoid valve 2 is energized. Only when it is necessary to switch to the side refrigerant circulation cycle can this be done by energizing the electromagnetic coil. Therefore, power consumption is reduced, the durability of the electromagnetic coil is improved, and an electromagnetic coil with a short-time rating can be used, so it is possible to downsize the electromagnetic coil. 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 communication state in the main valve is switched, and at this time, the high-pressure refrigerant and low-pressure refrigerant are instantaneously mixed. However, in the embodiment described above, since no switching movement occurs in the main valve after the compressor 4 is stopped, the above-mentioned impact noise is not generated.

Furthermore, during intermittent operation in the same refrigerant circulation cycle, such as ON-OFF control operation of the compressor accompanying temperature adjustment, the communication state of the main valve 1 is maintained on the circulation cycle side even during the stoppage. There is less movement of refrigerant when the engine is stopped, and the start-up is quickly performed when the engine is restarted.

Note that the pilot type four-way switching valve for refrigeration equipment of the present invention is not limited to the above embodiments,
Various modifications are possible. For example, the main valve 1 connects each pilot pressure chamber 21, 22 to a piston 23, 24.
Although the configuration is such that the high-pressure side is communicated with through the throttle holes 27 and 28 provided in the throttle holes, it is also possible to configure the high-pressure communication means instead of the throttle holes with external piping.
In addition, instead of the timer that determines the energization time to the pilot solenoid valve explained in Fig. 2, a positive characteristic thermistor is used, which has a resistance-time characteristic in which the temperature rises due to self-heating due to energization, and the resistance increases. You can also. Further, in the above embodiment, a device is described in which the pilot solenoid valve is energized and activated on the cooling cycle side, but the four-way switching valve of the present invention can also be applied to a device configuration in which the pilot solenoid valve is energized and activated on the warm cycle side. It is. Also,
The defrost bypass pipe in the above embodiment can also be used to shorten the pressure equalization time in the refrigerant pipe after the compressor is stopped.

(Effects of the Invention) As explained above, in the pilot type four-way switching valve for refrigeration equipment of the present invention, only when it is necessary to switch to the refrigerant circulation cycle on the side where the pilot solenoid valve is energized, Switching can be done by energizing for a certain period of time, and the stationary position after movement is maintained after energizing is stopped, which reduces power consumption and improves the electrical life of the electromagnetic coil. Generation of switching noise can be prevented.

[Brief explanation of drawings]

FIG. 1 is a refrigerant circuit diagram including a partial sectional view showing the overall configuration of an embodiment of the present invention, FIG. 2 is an operation circuit diagram of the device shown in FIG. 1, and FIG. 3 is a refrigerant circuit diagram showing the overall configuration of a conventional device. It is a circuit diagram. 1... Main valve, 2... Pilot solenoid valve, 4... Compressor, 6... First passage, 7... Suction piping (low pressure generation part),
8...Second passage, 9...Third passage, 10...Fourth passage, 21, 22...Pilot pressure chamber, 40...Pilot valve body, 42...First port, 43...Second port, 44... Third port, 49...Pilot valve body, 5
2...Return spring (biasing means).

Claims (1)

[Claims] 1 A pair of passages 6, 8 and another pair of passages 9, 1
0, the main valve 1 can change the communication state between each pair by switching between high and low pressure in the two pilot pressure chambers 21 and 22, and the low pressure generating section 7 in the refrigerant circuit accompanying the operation of the compressor 4. A pilot type four-way switching valve for a refrigeration system, which has a pilot solenoid valve 2 for switching the state of communication with each pilot pressure chamber 21, 22 of the main valve 1, wherein the pilot valve main body 40 of the pilot solenoid valve 2 has: A first port 42 connected to the low pressure generating section 7 in the refrigerant circuit, and second and third ports 43 and 44 connected to each of the pilot pressure chambers 21 and 22, respectively, are bored, A pilot valve body 49 is disposed within the pilot valve body 40, and when the pilot valve body 49 is moved by being energized, the third passage 4 is connected to the first passage 42.
4 is in communication with each other, and on the other hand, the second communication port 43 is configured to be switched to communicate with the first communication port 42 when the urging means 52 returns the main valve 1 in the energized state, and the communication state of the main valve 1 is switched. When a high-low pressure difference greater than the value required for is occurring in the refrigerant circuit,
The force in the return direction due to the refrigerant pressure on the first port 42 side acting on the pilot valve body 49 located on the moving side due to the energization, and the force in the return direction due to the refrigerant pressure on the first port 42 side
A pilot type four-way switching valve for a refrigeration system, characterized in that the resultant force of the refrigerant pressure on the third side and the force in the moving direction is larger than the return force of the urging means 52.