JP4056804B2 - Switching valve - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a switching valve, and more specifically, is connected to a supply flow path for supplying fluid from a pressure source, a discharge flow path for discharging fluid to the pressure source, and a fluid pressure operating mechanism operated by fluid pressure. The communication state between the first flow path and the second flow path is a state where the supply flow path and the first flow path communicate with each other and the second flow path and the discharge flow path communicate with each other. Alternatively, the present invention relates to a switching valve that switches to a state in which the supply flow path and the second flow path communicate with each other and the first flow path and the discharge flow path communicate with each other.
[0002]
[Prior art]
As a switching valve for switching the communication state of a plurality of flow paths to various states, a lift-type valve having a valve body that advances and retreats with respect to the valve port, or a valve body that slides on a member constituting the valve port Various types have been devised that employ a spool-type valve or the like equipped with. Here, in a fluid pressure operating device such as a fluid pressure jack, a high pressure fluid is used, but if the fluid is at a high pressure, fluid leakage is likely to occur, so a spool type valve is adopted as a switching valve. It is difficult to do. Therefore, when a high pressure fluid is handled, a lift type valve is generally employed. Conventionally, as a switching valve for appropriately switching the communication state of the four flow paths, a lift type open / close valve for opening and closing a single flow path, a lift type three-way valve for switching the communication state of the three flow paths, etc. A switching valve that performs a desired function as a whole by combining a plurality of valve devices.
[0003]
[Problems to be solved by the invention]
Since the conventional switching valve that appropriately switches the communication state of the four flow paths is configured by combining a plurality of valve devices, it is difficult to fit the whole in a compact manner. Further, when switching the four flow paths to a desired communication state, each valve device has to be individually operated, and the operation is complicated.
[0004]
The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a switching valve that can be compactly accommodated as a whole and that can switch a flow path by a simple operation.
[0005]
[Means for Solving the Problems]
The switching valve according to claim 1 is connected to a supply flow path for supplying fluid from a pressure source, a discharge flow path for discharging fluid to the pressure source, and a fluid pressure operating device operated by fluid pressure. A communication state between each of the first flow channel and the second flow channel, a state where the supply flow channel and the first flow channel communicate with each other and the second flow channel and the discharge flow channel communicate with each other; Or a switching valve for switching to a state in which the supply flow path and the second flow path communicate with each other and the first flow path and the discharge flow path communicate with each other, and the supply region to which the supply flow path is connected A main chamber having a discharge region to which the discharge channel is connected, a first chamber to which the first channel is connected, a second chamber to which the second channel is connected, and the main chamber A first valve port provided between a supply region and the first chamber; and a first valve port provided between the supply region of the main chamber and the second chamber. Is a second valve port that faces the first valve port,
A first valve portion that opens and closes the first valve port; and a second valve portion that opens and closes the second valve port. The first valve port and the second valve port are movably provided in a facing direction. And a main valve body that is biased in a direction to close the first valve port, and divides the main chamber into the supply region and the discharge region,
A first chamber side valve port provided in the main valve body and opening to the first chamber side and a second chamber side valve port opening to the second chamber side are formed, and the first chamber, A communication path that communicates between the second chamber and the discharge region, and is provided in the first chamber and is advanced and retracted to move forward, thereby closing the first chamber side valve port and the second valve port. A first valve body that moves the main valve body in a direction to close the first valve body, and the first valve body that is provided in the second chamber and is urged and advanced in a direction to close the second chamber side valve port A second valve body that is pushed by the second valve body to open the second chamber side valve port; and provided on the second chamber side, the main valve body closes the first valve port and the second valve port. A spring for the main valve body that urges in the direction to release the main valve body and the spring for the main valve body are provided separately on the second chamber side, And a spring for a second valve body that urges the body in a direction to close the second chamber side valve port, and the main valve body closes the first valve port and opens the second valve port. With the advancement of the first valve body from the opening position, the position of opening both the first valve port and the second valve port is closed, and the second valve port is closed and the first valve port is opened. The first valve port and the second valve port are moved from the position where the second valve port is closed and the first valve port is opened while the first valve body is retracted while moving to the opening position. Then, the first valve port is closed and the second valve port is moved to a position where the second valve port is opened .
[0006]
In the switching valve according to the present invention, the communication state in the four flow paths, that is, the supply flow path, the discharge flow path, the first flow path, and the second flow path, is communicated between the supply flow path and the first flow path and the second flow path. It is switched to a state where the flow path and the discharge flow path are communicated, or a state where the supply flow path and the second flow path are communicated and the first flow path and the discharge flow path are communicated. Switch the communication state of each channel.
[0007]
First, the first valve port and the second valve port are opened and closed by moving the main valve body between the first valve port and the second valve port facing each other. Switch to the first flow path or the second flow path. Then, by moving the first valve body and the second valve body, the first chamber side valve port and the second chamber side valve port of the communication path provided in the main valve body are opened and closed. Is switched to the first flow path or the second flow path.
[0008]
Here, the switching operation is performed by advancing and retracting the first valve body. However, when the first valve body is advanced, the first chamber-side valve port is closed by the first valve body, The second valve body is pushed, and the second chamber side valve port closed by the second valve body is opened. In addition, the main valve body is moved by the advancement of the first valve body, thereby opening the first valve port and closing the second valve port. Therefore, in a state where the first valve port is opened, that is, in a state where the supply flow path and the first flow path communicate, the state where the second chamber side valve port is opened, that is, the discharge flow path and the second flow path. The road is in communication.
[0009]
On the other hand, when the first valve body is moved backward, the first chamber side valve port closed by the first valve body is opened and the second valve body is moved by the urging force. The second chamber side valve port is closed. In addition, the main valve body is moved by the urging force as the first valve body is retracted to open the second valve port and close the first valve port. Therefore, in a state where the second valve port is opened, that is, in a state where the supply channel and the second channel communicate, the state where the first chamber side valve port is opened, that is, the discharge channel and the first flow The road is in communication.
[0010]
In the switching valve of the present invention, since the flow path is switched as described above, the flow path switching operation can be performed by a simple operation by a single operation to advance and retract the first valve body. Also, the first valve port and the second valve port facing each other are opened and closed by the main valve body, and the first chamber side valve port and the second chamber side valve port of the communication path provided in the main valve body are respectively the first valve body. And since it is the structure opened and closed by a 2nd valve body, it also becomes possible to store the whole switching valve compactly, especially compactly on one axis | shaft.
[0011]
Further, the main valve element opens and closes with respect to the first valve opening and the second valve opening to open and close each valve opening, and constitutes a so-called “lift valve” valve element. The first valve body and the second valve body open and close each valve port by moving forward and backward with respect to the first chamber side valve port and the second chamber side valve port, respectively. It constitutes the valve body of the “valve”. Here, the closing of the second valve port by the main valve body and the closing of the first chamber side valve port by the first valve body are firmly performed by the forward operation of the first valve body. On the other hand, the closing of the first valve port by the main valve body and the closing of the second chamber side valve port by the second valve body are performed firmly by adding the fluid pressure in the second chamber in addition to the respective urging forces. Is called. Therefore, leakage from the closed valve port hardly occurs, and it is suitable as a switching valve using a high-pressure fluid.
[0012]
According to a second aspect of the present invention, in the switching valve according to the first aspect, the first valve port and the second valve port are formed in a substantially circular shape, and the main valve body is separately provided. A first body and a second body formed on a body are provided, and the first valve portion is provided in the first body and is inserted into the first valve port to close the first valve port. The second valve portion is provided in the second body and is inserted into the second valve port to close the second valve port.
[0013]
In the present invention, since the first valve portion and the second valve portion of the main valve body are provided in the separate first body and second body, respectively, the first valve port and the second valve port facing each other are provided. Even if the misalignment occurs, the first and second bodies formed separately are displaced from each other to absorb the misalignment. Therefore, the first valve port is reliably closed by the first valve portion of the first body, and the second valve port is reliably closed by the second valve portion of the second body.
[0014]
According to a third aspect of the present invention, in the switching valve according to the first or second aspect, the main valve body includes a housing portion that forms the second chamber and that houses the second valve body. It is characterized by being recessed.
[0015]
In the present invention, at least a part of the second chamber is constituted by the accommodating portion recessed in the main valve body, and the second valve body is accommodated in the accommodating portion, so the length on the second chamber side is short. Thus, the length of the entire switching valve can be shortened.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
An example as an embodiment of a switching valve concerning the present invention is explained in detail based on a drawing. In this example, a pump is adopted as a pressure source, and an example in which the switching valve according to the present invention is applied to a fluid pressure jack as a fluid pressure operating device that is operated by fluid pressure from the pump is shown. The fluid pressure jack incorporates a manually driven pump and a switching valve for switching a fluid flow path in order to change a push-pull operation state, and stores a fluid such as oil. It is also equipped with a tank, and is reduced in size and weight as a whole. It is easy to carry, is easy to use, and is suitably used at work sites such as outdoors where it is difficult to secure a power source such as a power source. First, the fluid pressure jack will be described below.
[0017]
As shown in FIG. 1, the fluid pressure jack 10 includes a cylinder body 20 to which an attachment 25 attached to one member A that is pushed and pulled is mounted, and the other that is similarly pushed and pulled. An attachment 35 to be attached to the member B is attached, and a piston body 30 is attached to the cylinder body 20 so as to freely advance and retract.
[0018]
Here, in the fluid pressure jack 10, the pump 40 driven by the operation unit 44 such as a lever is built in the cylinder body 20, and the pump 40 is manually driven by operating the operation unit 44. . Further, when a tank 60 for storing fluid such as oil is rotatably supported on the side of the outer surface of the cylinder body 20 (arrow T), the fluid pressure jack 10 is used in the lateral direction as shown in the figure. In this case, the tank 60 can be turned to a vertical state.
[0019]
Next, the detailed structure of the fluid pressure jack 10 will be described. As shown in FIG. 2, a cylinder chamber 23 is recessed on the outer peripheral surface of the upper portion of the cylinder body 20, and the piston body 30 can be freely advanced and retracted above the cylinder body 20 so as to cover the cylinder chamber 23. It is fitted. Here, the piston body 30 includes a piston portion 31 extending from the inner peripheral surface to the cylinder chamber 23, and the piston chamber 31 partitions the cylinder chamber 23 into a first pressure chamber 21 and a second pressure chamber 22. Has been. The first pressure chamber 21 and the second pressure chamber 22 are formed in substantially the same cross-sectional area through the shaft portion 24 of the cylinder body 20.
[0020]
The cylinder body 20 has a fluid supply port 42 and a delivery port 41, and a pump 40 that delivers the fluid supplied from the supply port 42 from the delivery port 41 and a supply flow connected to the delivery port 41 of the pump 40. A passage K, a discharge passage H connected to the supply port 42 of the pump 40, a first passage R1 connected to the first pressure chamber 21, and a second passage R2 connected to the second pressure chamber 22. And a switching valve 50 for switching the communication state of the supply flow path K, the discharge flow path H, the first flow path R1, and the second flow path R2. Here, the switching valve 50 communicates the supply flow path K and the first flow path R1 and communicates the second flow path R2 and the discharge flow path H (solid line in the figure), or the supply flow path K. And the second flow path R2 are connected to each other and the first flow path R1 and the discharge flow path H are connected to each other (broken line in the drawing).
[0021]
The switching valve 50 includes an operation shaft (not shown) protruding from the cylinder body 20 and an operation portion (not shown) such as a handle attached to the operation shaft, and the operation portion is manually rotated. It is operated by moving. Further, the operation portion is formed wider than the operation shaft by a looped steel wire or flat plate, and is provided so as to be foldable with respect to the operation shaft. Therefore, the operation unit can be operated with a small turning force when operated, and can be compactly stored by folding when not operated.
[0022]
The supply flow path K is provided with a check valve 70 whose forward direction is the direction toward the switching valve 50, and the discharge flow path H is a reverse flow whose forward direction is the pump 40 side. A stop valve 70 is provided. In this example, the pump 40 is configured to send out the fluid supplied from the supply port 42 through the delivery port 41 by the forward and backward movement of the delivery piston 43.
[0023]
Furthermore, in this example, the tank 60 is connected to the discharge flow path H, and the fluid fluctuation amount in the flow path is compensated by storing the fluid in the tank 60. Here, the tank 60 is rotatably supported by the cylinder body 20 as described above. In addition, the tank 60 includes a sealing body 62 that moves according to the amount of fluid to be stored. The sealing body 62 seals the fluid stored in the tank 60. Therefore, by rotating the tank 60 according to the posture of the fluid pressure jack 10, not only can the discharge port 61 of the tank 60 be positioned downward, but even if the tank 60 is not rotated, the tank Since the fluid stored in 60 is sealed by the sealing body 62, the discharge port 61 is not exposed from the stored fluid. Thereby, whatever the posture of the fluid pressure jack 10 is, the fluid pressure jack 10 can be reliably operated.
[0024]
In the fluid pressure jack 10 of the present example configured as described above, the switching valve 50 is operated to connect the supply flow path K and the first flow path R1, and the second flow path R2 and the discharge flow path H. When the pump 40 is driven in a state where the two are connected (solid line in the figure), the fluid is sent to the first pressure chamber 21 to increase the volume of the first pressure chamber 21 and the fluid is discharged from the second pressure chamber 22. The volume of the second pressure chamber 22 decreases, the piston body 30 moves forward relative to the cylinder body 20, and operates on the push side. On the other hand, when the pump 40 is driven in a state where the supply flow path K and the second flow path R2 are in communication with each other and the first flow path R1 and the discharge flow path H are in communication with each other (broken line in the drawing), the second pressure chamber 22 is driven. As a result, the volume of the second pressure chamber 22 increases and the fluid is discharged from the first pressure chamber 21 to decrease the volume of the first pressure chamber 21, and the piston body 30 moves backward relative to the cylinder body 20. Then, it operates on the pull side. Here, since the first pressure chamber 21 and the second pressure chamber 22 have substantially the same cross-sectional area, the outputs obtained on the push side and the pull side are substantially the same.
[0025]
Next, the switching valve 50 will be described in detail with reference to FIGS. 3 and 4. 3 shows a state in which the supply flow path K and the first flow path R1 are communicated with each other, and the second flow path R2 and the discharge flow path H are in communication with each other. FIG. This shows a state in which the first flow path R1 and the discharge flow path H are communicated together with K communicating with the second flow path R2.
[0026]
The cylinder body 20 is provided with a through hole, and a main chamber 53 is formed at a central portion of the through hole. The main chamber 53 is connected to a supply channel K and a discharge channel H. Here, the supply flow path K is branched into two supply flow paths K1 and K2, the branched supply flow paths K1 and K2 are connected to both sides of the main chamber 53, and the discharge flow path H It is connected to the main chamber 53 between the supply flow paths K1, K2. In the main chamber 53, a supply region 53a is configured at a portion where the supply channels K1 and K2 are connected, and a discharge region 53b is configured at a portion where the discharge channel H is connected.
[0027]
A cap C1 is attached to one end side of the through hole, and a first chamber 51 is constituted by an internal space of the cap C1, and the first flow path R1 is connected to the first chamber 51. Yes. Further, the end portion of the cap C1 constitutes a first valve port 51a provided between the supply region 53a of the main chamber 53 and the first chamber 51. On the other hand, a cap C2 is attached to the other end side of the through-hole, and a second chamber 52 is formed by the internal space of the cap C2. The second chamber 52 has a second flow path R2 therein. It is connected. Further, a second valve port 52a provided between the supply region 53a of the main chamber 53 and the second chamber 52 is configured by the end portion of the cap C2. Here, the second valve port 52a is disposed so as to face the first valve port 51a.
[0028]
In the main chamber 53, a main valve body 80 is incorporated so as to be movable between the first valve port 51a and the second valve port 52a. A discharge area 53b is partitioned. Here, the main valve body 80 is urged toward the first valve port 51a by a spring 83 mounted in the internal space of the cap C2. The main valve body 80 has a first body 81 having a first valve portion 81a for opening and closing the first valve port 51a, and a second valve portion 82a for opening and closing the second valve port 52a. And a second body 82 formed separately and integrated with the first body 81. Here, the first valve portion 81a and the second valve portion 82a are inserted into the first valve port 51a and the second valve port 52a formed in a substantially circular shape, respectively, and the first valve port 51a and the second valve port 52a are inserted. The mouth 52a is closed.
[0029]
Further, a communication path 85 having a first chamber side valve port 85a that opens on the first chamber 51 side and a second chamber side valve port 85b that opens on the second chamber 52 side is inside the main valve body 80. It is provided in a penetrating manner. The communication path 85 also opens to the peripheral surface of the main valve body 80, communicates with the discharge region 53b of the main chamber 53, and communicates between the first chamber 51, the second chamber 52, and the discharge region 53b. To do.
[0030]
A first valve body 91 having an operation portion 91a on one end side is incorporated in the first chamber 51 formed by the internal space of the cap C1 so as to freely advance and retract. Here, the operation portion 91a of the first valve body 91 is screwed into the cap C1, and the first valve body 91 is advanced and retracted by the turning operation of the operation portion 91a. An insertion portion 91 b that is inserted into the communication path 85 of the main valve body 80 is provided on the other end side of the first valve body 91.
[0031]
A housing portion 84 is recessed at the end of the main valve body 80 on the second chamber 52 side, and the second chamber side valve port 85 b of the communication path 85 is opened in the housing portion 84. . Here, the accommodating part 84 comprises the 2nd chamber 52 with the internal space of the cap C2. And the accommodating part 84 accommodates the spherical 2nd valve body 92 which opens and closes the 2nd chamber side valve port 85b, and this 2nd valve body 92 is accommodated in the accommodating part 84 via the spring receiver B. The attached spring 93 is biased in a direction to close the second chamber side valve port 85b.
[0032]
Next, the operation mode of the switching valve 50 will be described. When the operation portion 91a of the first valve body 91 is rotated to advance the first valve body 91, the first valve 51 is opened at the end of the main valve body 80 on the first chamber 51 side as shown in FIG. The chamber side valve port 85 a is closed by the first valve body 91. Further, the second valve body 92 is pushed against the urging force of the spring 93 by the insertion portion 91b of the first valve body 91 inserted into the communication path 85 of the main valve body 80, and the second chamber side valve The mouth 85b is opened. When the first valve body 91 is further advanced, the main valve body 80 is pushed against the urging force of the spring 83 by the first valve body 91, and the main valve body 80 is closed. The first valve port 51a is opened and the second valve port 52a is closed. In this state, the supply flow path K and the first flow path R1 communicate with each other, the second flow path R2 and the discharge flow path H communicate with each other, and the fluid pressure jack 10 operates on the push side. Become.
[0033]
By the way, if the high pressure by the fluid is added to the 2nd chamber 52 in the state which the main valve body 80 obstruct | occluded the 1st valve port 51a, the main valve body 80 will be moved to the side which opens the 1st valve port 51a. Therefore, a great operating force is required. However, in the switching valve 50 of this example, the second valve body 92 is pushed and moved to the second chamber side valve port 85b before the main valve body 80 is moved to the side that opens the first valve port 51a. Therefore, the fluid pressure in the second chamber 52 passes through the communication path 85 of the main valve body 80 to the discharge flow path H. Therefore, in order to move the main valve body 80 to the side that opens the first valve port 51a, a large operating force is not required. In the state where the second valve body 92 closes the second chamber side valve port 85b, the fluid pressure of the second chamber 52 is applied to the second valve body 92. Is smaller than the main valve body 80 and has a small pressure receiving area, the force applied to the second valve body 92 is very small. Therefore, the second valve body 92 can be pushed by a small operating force, and the second chamber side valve port 85b can be opened without any trouble.
[0034]
When the operating portion 91a of the first valve body 91 is rotated from the state shown in FIG. 3 to retract the first valve body 91, the main valve body 80 is moved by the biasing force of the spring 83 as shown in FIG. It moves to the first valve port 51a side, thereby opening the second valve port 52a and closing the first valve port 51a. When the first valve body 91 is further retracted, the first chamber side valve port 85a closed by the first valve body 91 is opened, and the second valve body 92 is moved by the biasing force of the spring 93. Thus, the second valve side 92 closes the second chamber side valve port 85b. In this state, the supply flow path K and the second flow path R2 communicate with each other, the first flow path R1 and the discharge flow path H communicate with each other, and the fluid pressure jack 10 operates on the pull side. Become. In this state, in addition to the biasing force of the spring 83, the fluid pressure in the second chamber 52 is applied to the main valve body 80, and the first valve port 51a is firmly closed. In addition to the urging force of the spring 93, the fluid pressure in the second chamber 52 is applied to the second valve body 92, and the second chamber side valve port 85b is firmly closed.
[0035]
Although an example of the switching valve according to the present invention has been described above, the switching valve according to the present invention is not limited to this, and various modifications can be made without departing from the gist of the present invention.
[0036]
For example, not only a fluid pressure jack but also a switching valve that switches a fluid flow path in order to drive various fluid pressure actuated devices operated by a fluid, a pressure source such as a pump, and a fluid to be driven The switching valve may be separate from the pressure operating device and individually connected between the pressure source and the fluid pressure operating device. Furthermore, means for operating the first valve body to advance and retreat is not limited to manual operation, and may be operated by a drive device such as a solenoid.
[0037]
【The invention's effect】
According to the present invention described in detail above, the following effects can be obtained.
[0038]
According to the first aspect of the present invention, the flow path can be switched by a single and simple operation such as advancing and retracting the first valve body. Also, the first valve port and the second valve port facing each other are opened and closed by the main valve body, and the first chamber side valve port and the second chamber side valve port of the communication path provided in the main valve body are respectively the first valve body. And since it is the structure opened and closed by the 2nd valve body, the whole switching valve can also be stored in a compact.
[0039]
According to invention of Claim 2, since the 1st valve part and 2nd valve part of a main valve body are each provided in the separate 1st body and 2nd body, the 1st valve which mutually opposes Even if the center and the second valve port are misaligned, the first valve port and the second valve port can be reliably closed.
[0040]
According to the third aspect of the present invention, at least a part of the second chamber is configured by the accommodating portion recessed in the main valve body, and the second valve body is accommodated in the accommodating portion. The length on the chamber side can be shortened to shorten the entire length of the switching valve.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a fluid pressure jack employing a switching valve according to the present invention.
2 is an explanatory view schematically showing the structure of the fluid pressure jack of FIG. 1; FIG.
FIG. 3 is an explanatory view schematically showing the structure of a switching valve according to the present invention.
FIG. 4 is an explanatory view schematically showing the structure of a switching valve according to the present invention.
[Explanation of symbols]
K supply flow path H discharge flow path R1 first flow path R2 second flow path 10 Fluid pressure jack (fluid pressure operating device)
20 Cylinder body 30 Piston body 40 Pump (pressure source)
50 switching valve 51 first chamber 51a first valve port 52 second chamber 52a second valve port 53 main chamber 53a supply region 53b discharge region 60 tank 80 main valve body 81 first body 81a first valve portion 82 second body 82a Second valve portion 84 Housing portion 85 Communication path 85a First chamber side valve port 85b Second chamber side valve port 91 First valve body 92 Second valve body

Claims (3)

A supply flow path for supplying fluid from a pressure source, a discharge flow path for discharging fluid to the pressure source, a first flow path and a second flow path connected to a fluid pressure operating device operated by fluid pressure, respectively. The communication state between the channels is a state in which the supply channel and the first channel communicate with each other and the second channel and the discharge channel communicate with each other, or the supply channel and the second channel. A switching valve that switches to a state in which the first flow path and the discharge flow path are in communication with a flow path,
A main chamber having a supply area to which the supply flow path is connected and a discharge area to which the discharge flow path is connected, a first chamber to which the first flow path is connected, and the second flow path are connected. The second room,
A first valve port provided between the main chamber supply region and the first chamber, and a first valve port provided between the main chamber supply region and the second chamber, facing the first valve port. A second valve port,
A first valve portion that opens and closes the first valve port; and a second valve portion that opens and closes the second valve port. The first valve port and the second valve port are movably provided in a facing direction. And a main valve body that is biased in a direction to close the first valve port, and divides the main chamber into the supply region and the discharge region,
A first chamber side valve port provided in the main valve body and opening to the first chamber side and a second chamber side valve port opening to the second chamber side are formed, and the first chamber, A communication path connecting between the second chamber and the discharge area;
A first valve body that is provided in the first chamber and is advanced / retracted and moved forward to close the first chamber side valve port and move the main valve body in a direction to close the second valve port. When,
A second valve that is provided in the second chamber and is urged in a direction to close the second chamber side valve port, and is pushed by the first valve body that moves forward to open the second chamber side valve port. Body,
A spring for a main valve body that is provided on the second chamber side and biases the main valve body in a direction to close the first valve port and open the second valve port;
A spring for a second valve body that is provided separately from the main valve body spring and biases the second valve body in a direction to close the second chamber side valve port;
With
The main valve body closes both the first valve port and the second valve port from the position where the first valve port is closed and the second valve port is opened. From the position that closes the second valve port and opens the first valve port while closing the second valve port and opening the first valve port through the opening position, As the first valve body moves backward, both the first valve port and the second valve port are opened, and then the first valve port is closed and the second valve port is opened. A switching valve characterized by:   The first valve port and the second valve port are formed in a substantially circular shape, and the main valve body includes a first body and a second body formed separately from each other. The first valve portion is provided in the first body and is inserted into the first valve port to close the first valve port, and the second valve portion is provided in the second body and The switching valve according to claim 1, wherein the switching valve is inserted into the second valve port to close the second valve port.   3. The switching valve according to claim 1, wherein the main valve body is provided with a recessed portion that forms the second chamber and accommodates the second valve body. 4.

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