Valve device

Abstract

To provide a valve device that is caused to function as a three-way selector valve without enlarging the size.SOLUTION: A valve device includes: a valve chamber 7 in which a first valve body 15 and a second valve body 16 are stored in a housing 2; a diaphragm chamber 6 zoned by a diaphragm 5; and an intermediate chamber 8 disposed between the valve chamber 7 and the diaphragm chamber 6. A valve stem 3 includes a communication hole 14 for communicating between the valve chamber 7 and the diaphragm chamber 6 inside. The valve stem 3 is provided with the valve body 15 and the valve body 16. The first valve body 15 and the second valve body 16 are arranged in a first opening / closing position where as the valve stem 3 gets close to an actuator 4, the first valve body opens a first valve hole 12a, and the second valve body closes a second valve hole 13a, and the first valve body 15 and the second valve body 16 are arranged in a second opening / closing position where as the valve stem 3 gets away from the actuator 4, the first valve body closes the first valve hole 12a and the second valve body opens the second valve hole 13a. The valve stem 3 is provided with a pressure relief hole 14c communicating with the communication hole 14, and the pressure relief hole 14c is closed by a bearing 17 in the first opening / closing position, and is opened in the second opening / closing position.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The technology disclosed in this specification relates to a valve device that controls the flow of fluid in a flow path by reciprocating a valve body together with a valve shaft to open and close a valve hole.

Background Art

[0002] Conventionally, as this type of technology, for example, an electromagnetic valve (valve device) described in Patent Document 1 below is known. This valve device includes a coil that generates a magnetic force when energized, a fixed core with the coil disposed outside, and a movable core that reciprocates coaxially and oppositely to the fixed core. In order to reciprocate the movable core, the fixed core is configured to attract the movable core in the axial direction by the magnetic force generated by the coil. One end of the movable core in its axial direction faces the fixed core. The valve device further includes an operating chamber (including a diaphragm chamber) formed between the fixed core and the movable core, a biasing member that biases the movable core in a direction opposite to the attracting direction by the attracting force of the fixed core, a shaft (valve shaft) connected to the other end of the movable core, and a valve body fixed to one end of the valve shaft. Further, the valve device includes a housing in which the above-described members are accommodated, and a pressure chamber (valve chamber) and a partitioning chamber (intermediate chamber) where the fluid pressure acts are formed. The valve chamber and the intermediate chamber are partitioned by a partitioning wall (valve seat) having a valve hole. The intermediate chamber communicates with the outside through a communication passage (outlet) formed in the housing. The valve chamber communicates with the outside through an inlet formed in the housing. Further, a diaphragm that partitions between the diaphragm chamber and the intermediate chamber is provided in the housing. And the valve shaft penetrates from one end portion to the other end portion thereof and has a through hole (communication hole) that communicates the diaphragm chamber and the valve chamber. That is, this valve device functions as a "two-way switching valve" that opens and closes between the intermediate chamber and the valve chamber by operating the valve body.

[0003] Therefore, according to the configuration of this valve device, the fluid pressures in the valve chamber and the diaphragm chamber become equal through the communication hole of the valve shaft, and a pressure cancellation effect is obtained. For this reason, the pressure received by the valve body due to the fluid pressure in the valve chamber and the pressure received by the diaphragm due to the fluid pressure in the diaphragm chamber act in opposite directions to each other, and the pressure received by the valve shaft is relatively reduced.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, the valve device described in Patent Document 1 functioned as a two-way switching valve. However, in the same way aiming at the pressure cancellation effect, a valve device can be assumed that has a communication hole in the valve shaft and functions as a three-way switching valve having one inlet and two outlets in the flow path. In this case, although the fluid pressure received by the valve body when flowing fluid from one outlet can be cancelled, when flowing fluid from the other outlet, the fluid pressure acting on the valve body increases. Therefore, it is necessary to increase the suction force of the fixed core in order to drive the valve body, and for this reason, the coil becomes large, and there is a possibility that the valve device becomes large-sized.

[0006] This disclosed technology has been made in view of the above circumstances, and its purpose is to provide a valve device that functions as a three-way switching valve without increasing in size.

Means for Solving the Problems

[0007] To achieve the above object, the technology according to claim 1 includes a housing including a fluid flow path, a valve seat provided in the flow path and having a valve hole, a valve body provided in the flow path so as to be seatable on the valve seat to open and close the valve hole, a valve shaft provided in the housing so as to be axially movable, including one end portion and the other end portion, with the valve body provided at the one end portion, an actuator connected to the housing and having the other end portion of the valve shaft drivingly connected thereto to reciprocate the valve shaft in the axial direction, a diaphragm disposed between the housing and the actuator and having the valve shaft penetrating therethrough, and a diaphragm chamber provided between the housing and the actuator, partitioned by the diaphragm from the side of the housing, and having the other end portion of the valve shaft disposed therein. In the valve device, the flow path includes a valve chamber in which the valve body is accommodated, an intermediate chamber partitioned by the diaphragm from the diaphragm chamber and disposed between the valve chamber and the diaphragm chamber, an inlet and a first outlet of the fluid provided in the valve chamber, and a second outlet of the fluid provided in the intermediate chamber. The valve seat includes a first valve seat having a first valve hole disposed corresponding to the first outlet, and a second valve seat disposed between the valve chamber and the intermediate chamber and having a second valve hole disposed on the same axis as the first valve hole. The valve shaft is disposed so as to be axially reciprocally movable on the axes of the first valve hole and the second valve hole, and a communication hole for communicating between the valve chamber and the diaphragm chamber is provided therein. The valve body includes a first valve body for opening and closing the first valve hole and a second valve body for opening and closing the second valve hole in accordance with the axial reciprocation of the valve shaft. When the valve shaft moves in the direction approaching the actuator, the first valve body is disposed at a first opening / closing position where the first valve body opens the first valve hole and the second valve body closes the second valve hole. When the valve shaft moves in the direction away from the actuator, the first valve body is disposed at a second opening / closing position where the first valve body closes the first valve hole and the second valve body opens the second valve hole. A bearing for axially reciprocally supporting the valve shaft is provided in the intermediate chamber. A pressure relief hole communicating with the communication hole corresponding to the intermediate chamber is provided in the valve shaft. The pressure relief hole is configured to be closed in alignment with the bearing when the first valve body and the second valve body are disposed at the first opening / closing position, and to be opened away from the bearing when the first valve body and the second valve body are disposed at the second opening / closing position.

[0008] According to the configuration of the above technology, when the first valve body and the second valve body are arranged at the first opening / closing position, the pressure relief hole is aligned with the bearing and closed. At this time, the pressure of the fluid acting on the valve chamber from the inlet acts in the direction of approaching the valve shaft to the actuator via the second valve body, but the same pressure also acts on the diaphragm chamber through the communication hole, and acts on the valve shaft through the diaphragm in the direction away from the actuator, that is, in the direction canceling the pressure acting on the second valve body. Therefore, the force required to switch the first valve body and the second valve body from the first opening / closing position to the second opening / closing position is reduced by the amount that cancels the pressure of the fluid acting on the valve shaft via the second valve body. On the contrary, when the first valve body and the second valve body are arranged at the second opening / closing position, the pressure relief hole is opened while being separated from the bearing. At this time, the pressure of the fluid acting on the valve chamber from the inlet acts in the direction of separating the valve shaft from the actuator via the first valve body, but the pressure acting on the communication hole escapes (is canceled) to the intermediate chamber through the pressure relief hole and does not act on the diaphragm chamber. Therefore, the force required to switch the first valve body and the second valve body from the second opening / closing position to the first opening / closing position is reduced by the amount that the fluid pressure does not act on the diaphragm chamber.

[0009] In order to achieve the above object, the technique according to claim 2 includes a housing including a fluid flow path, a valve seat provided in the flow path and having a valve hole, a valve body provided in the flow path so as to be seatable on the valve seat to open and close the valve hole, a valve shaft provided in the housing so as to be axially movable, including one end portion and the other end portion, with the valve body provided at the one end portion, an actuator connected to the housing and having the other end portion of the valve shaft drivingly connected thereto to reciprocate the valve shaft in the axial direction, a diaphragm disposed between the housing and the actuator and through which the valve shaft penetrates, and a diaphragm chamber provided between the housing and the actuator, partitioned by the diaphragm from the side of the housing, and having the other end portion of the valve shaft disposed therein. In the valve device, the flow path is partitioned by the diaphragm from the diaphragm chamber, and includes a first valve chamber in which the valve body is accommodated, an intermediate chamber disposed adjacent to the first valve chamber, a second valve chamber disposed adjacent to the intermediate chamber, a fluid inlet provided in the intermediate chamber, a first fluid outlet provided in the second valve chamber, and a second fluid outlet provided in the first valve chamber. The valve seat includes a first valve seat having a first valve hole disposed between the second valve chamber and the intermediate chamber, and a second valve seat disposed between the first valve chamber and the intermediate chamber and having a second valve hole disposed on the same axis as the first valve hole. The valve shaft is disposed so as to be axially reciprocally movable on the axes of the first valve hole and the second valve hole, and a communication hole for communicating between the intermediate chamber and the diaphragm chamber is provided therein. The valve body includes a first valve body for opening and closing the first valve hole and a second valve body for opening and closing the second valve hole as the valve shaft reciprocates in the axial direction. When the valve shaft moves in a direction approaching the actuator, the first valve body closes the first valve hole and the second valve body opens the second valve hole, and the valve shaft is disposed at a first opening / closing position. When the valve shaft moves in a direction away from the actuator, the first valve body opens the first valve hole and the second valve body closes the second valve hole, and the valve shaft is disposed at a second opening / closing position. A bearing for axially reciprocally supporting the valve shaft is provided in the first valve chamber, and a pressure relief hole communicating with the communication hole corresponding to the first valve chamber is provided in the valve shaft. The pressure relief hole is configured to be closed in alignment with the bearing when the first valve body and the second valve body are disposed at the second opening / closing position, and to be opened away from the bearing when the first valve body and the second valve body are disposed at the first opening / closing position.

[0010] According to the configuration of the above-described technology, when the first valve body and the second valve body are disposed at the second opening / closing position, the pressure relief hole is aligned with the bearing and closed. At this time, the pressure of the fluid acting from the inlet to the intermediate chamber acts in a direction to bring the valve shaft closer to the actuator via the second valve body. However, the same pressure also acts on the diaphragm chamber through the communication hole and acts on the diaphragm in a direction away from the actuator, that is, in a direction to cancel the pressure acting on the second valve body. Therefore, the force required to switch the first valve body and the second valve body from the second opening / closing position to the first opening / closing position is reduced by an amount that cancels the pressure of the fluid acting on the valve shaft via the second valve body. On the other hand, when the first valve body and the second valve body are disposed at the first opening / closing position, the pressure relief hole is opened while being separated from the bearing. At this time, the pressure of the fluid acting from the inlet to the intermediate chamber acts in a direction to move the valve shaft away from the actuator via the first valve body. However, the pressure acting on the communication hole escapes (is canceled) to the first valve chamber through the pressure relief hole and does not act on the diaphragm chamber. Therefore, the force required to switch the first valve body and the second valve body from the first opening / closing position to the second opening / closing position is reduced by an amount that the pressure of the fluid acting on the intermediate chamber acts on the valve shaft in a direction away from the actuator via the first valve body.

[0011] In order to achieve the above object, the technology according to claim 3 is, in the technology according to claim 1 or 2, characterized in that a pressure derivation hole for deriving the pressure of the fluid acting on the communication hole to the diaphragm chamber and a pressure introduction hole for introducing the pressure of the fluid in the valve chamber to the communication hole are formed in the valve shaft, and when the inner diameter of the pressure derivation hole is larger than the inner diameter of the pressure introduction hole, the inner diameter of the pressure relief hole is set to be larger than the inner diameter of the pressure introduction hole.

[0012] According to the configuration of the above-described technology, in addition to the action of the technology according to claim 1 or 2, when the inner diameter of the pressure derivation hole is larger than the inner diameter of the pressure introduction hole, when the pressure relief hole is closed, the pressure of the fluid in the valve chamber introduced from the pressure introduction hole to the communication hole is surely introduced to the diaphragm chamber through the pressure derivation hole. However, when the pressure relief hole is opened, the pressure of the fluid in the valve chamber introduced from the pressure introduction hole to the communication hole is surely introduced to the intermediate chamber through the pressure relief hole.

[0013] In order to achieve the above object, the technique according to claim 4 is, in the technique according to claim 1 or 2, on the valve shaft, a pressure derivation hole for deriving the pressure of the fluid acting on the communication hole into the diaphragm chamber and a pressure introduction hole for introducing the pressure of the fluid in the valve chamber into the communication hole are formed. When the inner diameter of the pressure derivation hole is smaller than the inner diameter of the pressure introduction hole, the inner diameter of the pressure relief hole is set to be larger than the inner diameter of the pressure derivation hole.

[0014] According to the configuration of the above technique, in addition to the action of the technique according to claim 1 or 2, when the inner diameter of the pressure derivation hole is smaller than the inner diameter of the pressure introduction hole, when the pressure relief hole is closed, the pressure of the fluid in the valve chamber introduced from the pressure introduction hole into the communication hole is surely introduced into the diaphragm chamber through the pressure derivation hole. However, when the pressure relief hole is opened, the pressure of the fluid in the valve chamber introduced from the pressure introduction hole into the communication hole is surely introduced into the intermediate chamber through the pressure relief hole.

[0015] In order to achieve the above object, the technique according to claim 5 is, in the technique according to claim 1 or 2, the actuator includes a coil that generates a magnetic force when energized, a fixed core with the coil disposed outside, a movable core that is coaxially opposed to the fixed core and is reciprocally movable, and is connected to the valve shaft, and a biasing member for biasing the movable core in a predetermined direction. In order to reciprocate the valve shaft in the axial direction, the fixed core is configured to axially attract the movable core by the magnetic force generated by the coil.

[0016] According to the configuration of the above technique, in addition to the action of the technique according to claim 1 or 2, in the actuator, in order to reciprocate the valve shaft in the axial direction, the fixed core is configured to axially attract the movable core by the magnetic force generated by the coil. Therefore, the force required to switch the first valve body and the second valve body between the first opening / closing position and the second opening / closing position can be reduced by the amount by which the force with which the fixed core attracts the movable core can be reduced.

[0017] In order to achieve the above object, the technique according to claim 6 is, in the technique according to claim 3, the actuator includes a coil that generates magnetic force when energized, a fixed core with the coil disposed outside, a movable core that is coaxially opposed to the fixed core and is reciprocally movable, and is connected to the valve shaft, and a biasing member for biasing the movable core in a predetermined direction. To reciprocate the valve shaft in the axial direction, the fixed core is configured to axially attract the movable core by the magnetic force generated by the coil.

[0018] According to the configuration of the above technique, in addition to the action of the technique according to claim 3, in the actuator, to reciprocate the valve shaft in the axial direction, the fixed core is configured to axially attract the movable core by the magnetic force generated by the coil. Therefore, the force required to switch the first valve body and the second valve body between the first opening / closing position and the second opening / closing position can be reduced by the amount by which the force with which the fixed core attracts the movable core can be reduced.

[0019] In order to achieve the above object, the technique according to claim 7 is, in the technique according to claim 4, the actuator includes a coil that generates magnetic force when energized, a fixed core with the coil disposed outside, a movable core that is coaxially opposed to the fixed core and is reciprocally movable, and is connected to the valve shaft, and a biasing member for biasing the movable core in a predetermined direction. To reciprocate the valve shaft in the axial direction, the fixed core is configured to axially attract the movable core by the magnetic force generated by the coil.

[0020] According to the configuration of the above technique, in addition to the action of the technique according to claim 4, in the actuator, to reciprocate the valve shaft in the axial direction, the fixed core is configured to axially attract the movable core by the magnetic force generated by the coil. Therefore, the force required to switch the first valve body and the second valve body between the first opening / closing position and the second opening / closing position can be reduced by the amount by which the force with which the fixed core attracts the movable core can be reduced.

[0021] In order to achieve the above object, the technique according to claim 8 is directed to the technique according to claim 5, wherein the biasing member is a spring that biases the movable iron core in a direction away from the fixed iron core.

[0022] According to the configuration of the above technique, in addition to the action of the technique according to claim 5, since the movable iron core is biased in a direction away from the fixed iron core by the spring, the valve shaft is biased in a direction away from the actuator together with the movable iron core, and the first valve body and the second valve body are biased toward the second opening / closing position. That is, the first valve body and the second valve body are biased in a direction opposite to the attracting force of the fixed iron core by the spring.

[0023] In order to achieve the above object, the technique according to claim 9 is directed to the technique according to claim 6, wherein the biasing member is a spring that biases the movable iron core in a direction away from the fixed iron core.

[0024] According to the configuration of the above technique, in addition to the action of the technique according to claim 6, since the movable iron core is biased in a direction away from the fixed iron core by the spring, the valve shaft is biased in a direction away from the actuator together with the movable iron core, and the first valve body and the second valve body are biased toward the second opening / closing position. That is, the first valve body and the second valve body are biased in a direction opposite to the attracting force of the fixed iron core by the spring.

[0025] In order to achieve the above object, the technique according to claim 10 is directed to the technique according to claim 7, wherein the biasing member is a spring that biases the movable iron core in a direction away from the fixed iron core.

[0026] According to the configuration of the above technique, in addition to the action of the technique according to claim 7, since the movable iron core is biased in a direction away from the fixed iron core by the spring, the valve shaft is biased in a direction away from the actuator together with the movable iron core, and the first valve body and the second valve body are biased toward the second opening / closing position. That is, the first valve body and the second valve body are biased in a direction opposite to the attracting force of the fixed iron core by the spring.

[0027] In order to achieve the above object, the technique according to claim 11 is, in the technique according to claim 8, characterized in that the area of the first pressure receiving surface of the diaphragm, on which fluid pressure acts in the axial direction of the valve shaft facing the diaphragm chamber, and the area of the second pressure receiving surface of the second valve body, on which fluid pressure acts in the axial direction of the valve shaft facing the valve chamber, are set to be substantially the same.

[0028] According to the configuration of the above technique, in addition to the action of the technique according to claim 8, the area of the first pressure receiving surface of the diaphragm and the area of the second pressure receiving surface of the second valve body are set to be substantially the same. Therefore, when the first valve body and the second valve body are arranged at the first opening / closing position, the fluid pressure acting on the valve shaft via the second valve body is canceled out by the fluid pressure acting on the valve shaft via the diaphragm through the communication hole.

[0029] In order to achieve the above object, the technique according to claim 12 is, in the technique according to claim 8, characterized in that the area of the fourth pressure receiving surface of the first valve body, on which fluid pressure acts in the axial direction of the valve shaft facing the valve chamber, is set to be smaller than the area of the second pressure receiving surface of the second valve body, on which fluid pressure acts in the axial direction of the valve shaft facing the valve chamber.

[0030] According to the configuration of the above technique, in addition to the action of the technique according to claim 8, when switching the opening / closing positions of the first valve body and the second valve body, the generated magnetic force required for the coil is greater when the first valve body and the second valve body are arranged at the second opening / closing position than when they are arranged at the first opening / closing position. Therefore, by setting the area of the fourth pressure receiving surface of the first valve body to be smaller than the area of the second pressure receiving surface of the second valve body, the generated magnetic force required for the coil is reduced.

Effect of the Invention

[0031] According to the technique described in claim 1, the driving force of the actuator can be reduced, and thereby the valve device can function as a three-way switching valve without increasing the size of the valve device.

[0032] According to the technique described in claim 2, the driving force of the actuator can be reduced, and thereby the valve device can function as a three-way switching valve without increasing the size of the valve device.

[0033] According to the technology described in claim 3, in addition to the effects of the technology described in claim 1 or 2, in any case where the first valve body and the second valve body are arranged at the first opening / closing position or the second opening / closing position, the pressure of the fluid introduced into the communication hole of the valve shaft can be surely offset or canceled.

[0034] According to the technology described in claim 4, in addition to the effects of the technology described in claim 1 or 2, in any case where the first valve body and the second valve body are arranged at the first opening / closing position or the second opening / closing position, the pressure of the fluid introduced into the communication hole of the valve shaft can be surely offset or canceled.

[0035] According to the technology described in claim 5, in addition to the effects of the technology described in claim 1 or 2, the coil can be miniaturized, and thereby the actuator can be miniaturized.

[0036] According to the technology described in claim 6, in addition to the effects of the technology described in claim 3, the coil can be miniaturized, and thereby the actuator can be miniaturized.

[0037] According to the technology described in claim 7, in addition to the effects of the technology described in claim 4, the coil can be miniaturized, and thereby the actuator can be miniaturized.

[0038] According to the technology described in claim 8, in addition to the effects of the technology described in claim 5, when switching the first valve body and the second valve body to the second opening / closing position, the driving force of the actuator can be reduced by the amount of the biasing force of the spring.

[0039] According to the technology described in claim 9, in addition to the effects of the technology described in claim 6, when switching the first valve body and the second valve body to the second opening / closing position, the driving force of the actuator can be reduced by the amount of the biasing force of the spring.

[0040] According to the technique described in claim 10, in addition to the effect of the technique described in claim 7, when switching the first valve body and the second valve body to the second opening / closing position, the driving force of the actuator can be reduced by the amount of the biasing force of the spring.

[0041] According to the technique described in claim 11, in addition to the effect of the technique described in claim 8, when switching the first valve body and the second valve body to the first opening / closing position, the driving force of the actuator can be further reduced by the amount by which the pressure of the fluid acting on the valve shaft via the second valve body is canceled out, and thereby the actuator can be further miniaturized.

[0042] According to the technique described in claim 12, in addition to the effect of the technique described in claim 8, the coil can be further miniaturized, and thereby the actuator can be further miniaturized.

Brief Description of the Drawings

[0043]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Modes for Carrying Out the Invention

[0044] Hereinafter, embodiments in which the valve device is embodied will be described.

[0045] <First Embodiment> First, the first embodiment will be described in detail with reference to the drawings.

[0046] [Overview of Valve Device] Figs. 1 and 2 show a schematic cross-section of the valve device 1 of this embodiment. This valve device 1 is assumed to be a solenoid valve that functions as a three-way switching valve. Fig. 1 shows the state where the valve device 1 is electrically off, and Fig. 2 shows the state where the valve device 1 is electrically on. As shown in Figs. 1 and 2, this valve device 1 includes a housing 2 including fluid flow paths 7 to 11, valve seats 12 and 13 provided in the flow paths 7 to 11 and having valve holes 12a and 13a, valve bodies 15 and 16 provided in the flow paths 7 to 11 so as to be seatable on the valve seats 12 and 13 to open and close the valve holes 12a and 13a, a valve shaft 3 provided in the housing 2 so as to be axially movable and including one end portion 3a and the other end portion 3b, with the valve bodies 15 and 16 provided at the one end portion 3a, an actuator 4 connected to the housing 2 and having the other end portion 3b of the valve shaft 3 drivingly connected thereto for reciprocating the valve shaft 3 in the axial direction, a diaphragm 5 disposed between the housing 2 and the actuator 4 and through which the valve shaft 3 penetrates, and a diaphragm chamber 6 provided between the housing 2 and the actuator 4, partitioned by the diaphragm 5 from the side of the housing 2, and in which the other end portion 3b of the valve shaft 3 is disposed.

[0047] [Configuration of Housing] The flow paths 7 to 11 include a valve chamber 7 in which the valve bodies 15 and 16 are accommodated, an intermediate chamber 8 partitioned by the diaphragm 5 from the diaphragm chamber 6 and disposed between the valve chamber 7 and the diaphragm chamber 6, a fluid inlet 9 and a first outlet 10 provided in the valve chamber 7, and a second outlet 11 of the fluid provided in the intermediate chamber 8. Pipes (not shown) of the fluid are respectively connected to the inlet 9, the first outlet 10, and the second outlet 11.

[0048] The valve seats 12 and 13 include a first valve seat 12 having a first valve hole 12a disposed corresponding to the first outlet 10, and a second valve seat 13 disposed between the valve chamber 7 and the intermediate chamber 8 and having a second valve hole 13a disposed on the same axis as the first valve hole 12a.

[0049] The valve shaft 3 is disposed to be axially reciprocally movable on the axis of the first valve hole 12a and the second valve hole 13a. Inside the valve shaft 3, a communication hole 14 for communicating between the valve chamber 7 and the diaphragm chamber 6 is provided. That is, at the other end of the valve shaft 3, a pressure derivation hole 14a having the same inner diameter as the inner diameter of the communication hole 14 and for deriving the pressure of the fluid acting on the communication hole 14 to the diaphragm chamber 6 is formed. On the other hand, on the outer periphery of one end portion 3a of the valve shaft 3, a pressure introduction hole 14b for introducing the pressure of the fluid in the valve chamber 7 into the communication hole 14 is formed. In this embodiment, the inner diameter of the pressure introduction hole 14b is set smaller than the inner diameter of the pressure derivation hole 14a.

[0050] The valve bodies 15 and 16 include a first valve body 15 for opening and closing the first valve hole 12a and a second valve body 16 for opening and closing the second valve hole 13a in the valve chamber 7 as the valve shaft 3 reciprocates axially. And as shown in FIG. 2, this valve device 1 is configured to be disposed at a first opening / closing position where the first valve body 15 separates from the first valve seat 12 to open the first valve hole 12a and the second valve body 16 seats on the second valve seat 13 to close the second valve hole 13a when the valve shaft 3 moves in the direction approaching the actuator 4. Also, as shown in FIG. 1, this valve device 1 is configured to be disposed at a second opening / closing position where the first valve body 15 seats on the first valve seat 12 to close the first valve hole 12a and the second valve body 16 separates from the second valve seat 13 to open the second valve hole 13a when the valve shaft 3 moves in the direction away from the actuator 4.

[0051] In the intermediate chamber 8, a bearing 17 for supporting the valve shaft 3 so as to be reciprocable in the axial direction is provided. This bearing 17 is integrally formed with the housing 2. On the outer periphery of the valve shaft 3, a pressure relief hole 14c communicating with the communication hole 14 corresponding to the intermediate chamber 8 is provided. As shown in FIG. 2, the pressure relief hole 14c is configured to be closed in alignment with the bearing 17 when the first valve body 15 and the second valve body 16 are arranged at the first opening / closing position. Further, as shown in FIG. 1, the pressure relief hole 14c is configured to be opened while being separated from the bearing 17 when the first valve body 15 and the second valve body 16 are arranged at the second opening / closing position. In this embodiment, the inner diameter of the pressure relief hole 14c is set larger than the inner diameter of the pressure introduction hole 14b.

[0052] In this embodiment, the first area of the first pressure receiving surface 5a of the diaphragm 5, which faces the diaphragm chamber 6 and on which the fluid pressure acts in the axial direction of the valve shaft 3, and the second area of the second pressure receiving surface 16a of the second valve body 16, which faces the valve chamber 7 and on which the fluid pressure acts in the axial direction of the valve shaft 3, are set to be substantially the same.

[0053] [Configuration of Actuator] As shown in FIGS. 1 and 2, the actuator 4 includes a coil 21 that generates a magnetic force when energized, a fixed core 22 with the coil 21 disposed outside, a movable core 23 that is coaxially opposed to the fixed core 22 and is reciprocable and is connected to the valve shaft 3, and a spring 24 for biasing the movable core 23 in a predetermined direction. In this embodiment, the spring 24 is disposed between the fixed core 22 and the movable core 23. The spring 24 corresponds to an example of the biasing member of this disclosed technology. In this embodiment, as the predetermined direction, it biases the movable core 23 in a direction away from the fixed core 22. In other words, the spring 24 biases the first valve body 15 and the second valve body 16 in a direction to be arranged at the second opening / closing position via the movable core 23 and the valve shaft 3.

[0054] The fixed iron core 22 forms a bottomed cylindrical shape that opens downward in FIGS. 1 and 2, and the spring 24 is arranged in the recess 22a thereof. The movable iron core 23 forms a substantially cylindrical shape with both ends open in FIGS. 1 and 2. The other end 3b of the valve shaft 3 is fitted and connected into the internal hollow 23a, and the pressure derivation hole 14a of the communication hole 14 of the valve shaft 3 communicates with the hollow 23a. As a result, the communication hole 14 of the valve shaft 3 communicates with the diaphragm chamber 6.

[0055] This actuator 4 is configured such that the fixed iron core 22 axially attracts the movable iron core 23 by the magnetic force generated by the coil 21 in order to reciprocate the valve shaft 3 in the axial direction. The actuator 4 further includes a resin casing 25 that covers the outer periphery of the fixed iron core 22, and a connector 25a is integrally provided on the casing 25. A terminal 26 connected to the coil 21 is provided on the connector 25a. Then, power is supplied (turned on) and not supplied (turned off) to the coil 21 via this terminal 26.

[0056] [Operation and Effect of the Valve Device] According to the configuration of the valve device 1 of this embodiment described above, as shown in FIG. 2, when the first valve body 15 and the second valve body 16 are arranged at the first opening / closing position, the pressure relief hole 14c is aligned with the bearing 17 and closed. At this time, the pressure of the fluid acting from the inlet 9 to the valve chamber 7 (indicated by the thick dashed arrow in FIG. 2) acts on the valve shaft 3 via the second valve body 16 in a direction approaching the actuator 4, but the same pressure (indicated by the dashed arrow in FIG. 2) also acts on the diaphragm chamber 6 through the communication hole 14 and acts on the valve shaft 3 via the diaphragm 5 in a direction away from the actuator 4, that is, in a direction canceling the pressure acting on the second valve body 16. Therefore, the force required to switch the first valve body 15 and the second valve body 16 from the first opening / closing position to the second opening / closing position is reduced by an amount that cancels the pressure of the fluid acting on the valve shaft 3 via the second valve body 16.

[0057] On the other hand, as shown in FIG. 1, when the first valve body 15 and the second valve body 16 are arranged at the second opening / closing position, the pressure relief hole 14c is opened while being separated from the bearing 17. At this time, the pressure of the fluid acting on the valve chamber 7 from the inlet 9 (shown by the thick dashed arrow in FIG. 1) acts on the valve shaft 3 via the first valve body 15 in a direction away from the actuator 4, but the pressure acting on the communication hole 14 (shown by the dashed arrow in FIG. 1) escapes (is canceled) to the intermediate chamber 8 through the pressure relief hole 14c and does not act on the diaphragm chamber 6. Therefore, the force required to switch the first valve body 15 and the second valve body 16 from the second opening / closing position to the first opening / closing position is reduced by the amount that the fluid pressure does not act on the diaphragm chamber 6. For this reason, the driving force of the actuator 4 can be reduced, and thereby the valve device 1 can function as a three-way switching valve without increasing its size.

[0058] According to the configuration of this embodiment, in the actuator 4, in order to reciprocate the valve shaft 3 in the axial direction, the fixed core 22 is configured to axially attract the movable core 23 by the magnetic force generated by the coil 21. Therefore, the force with which the fixed core 22 attracts the movable core 23 can be reduced by the amount that the force required to switch the first valve body 15 and the second valve body 16 between the first opening / closing position and the second opening / closing position is reduced. For this reason, the coil 21 can be miniaturized, and thereby the actuator 4 can be miniaturized.

[0059] According to the configuration of this embodiment, since the movable core 23 is biased in a direction away from the fixed core 22 by the spring 24, the valve shaft 3 together with the movable core 23 is biased in a direction away from the actuator 4, and the first valve body 15 and the second valve body 16 are biased toward the second opening / closing position shown in FIG. 1. That is, the first valve body 15 and the second valve body 16 are biased in a direction opposite to the attracting force of the fixed core 22 by the spring 24. For this reason, the driving force of the actuator 4 when switching the first valve body 15 and the second valve body 16 to the second opening / closing position can be reduced by the biasing force of the spring 24.

[0060] According to the configuration of this embodiment, the first area of the first pressure receiving surface 5a of the diaphragm 5 and the second area of the second pressure receiving surface 16a of the second valve body 16 are set to be substantially the same. Therefore, as shown in FIG. 2, when the first valve body 15 and the second valve body 16 are arranged at the first opening / closing position, the pressure of the fluid acting on the valve shaft 3 via the second valve body 16 is canceled out by the pressure of the fluid acting on the valve shaft 3 via the diaphragm 5 through the communication hole 14. For this reason, the driving force of the actuator 4 when switching the first valve body 15 and the second valve body 16 to the first opening / closing position can be further reduced by the amount canceled out by the pressure of the fluid acting on the valve shaft 3 via the second valve body 16, and thereby the actuator 4 can be further miniaturized.

[0061] According to the configuration of this embodiment, when the inner diameter of the pressure derivation hole 14a is larger than the inner diameter of the pressure introduction hole 14b, when the pressure relief hole 14c is closed, the pressure of the fluid in the valve chamber 7 introduced from the pressure introduction hole 14b into the communication hole 14 is surely introduced into the diaphragm chamber 6 via the pressure derivation hole 14a. However, when the pressure relief hole 14c is opened, the pressure of the fluid in the valve chamber 7 introduced from the pressure introduction hole 14b into the communication hole 14 is surely introduced into the intermediate chamber 8 via the pressure relief hole 14c. For this reason, in any case where the first valve body 15 and the second valve body 16 are arranged at the first opening / closing position or the second opening / closing position, the pressure of the fluid introduced into the communication hole 14 of the valve shaft 3 can be surely canceled out.

[0062] <Second Embodiment> Next, the second embodiment will be described in detail with reference to the drawings. In the following description, components equivalent to those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted, and the description will focus on the different points.

[0063] [Configuration of Actuator] In this embodiment, it is different from the first embodiment in the configuration of the first valve seat 12 and the first valve body 15. FIGS. 3 and 4 show a schematic cross-sectional view of the valve device 1 of this embodiment. FIG. 3 shows a state where the valve device 1 is electrically turned off as in FIG. 1, and FIG. 4 shows a state where the valve device 1 is electrically turned on as in FIG. 2.

[0064] That is, in this embodiment, the maximum outer diameter of the first valve body 15 is reduced (e.g., by about 20%) compared to the maximum outer diameter of the first valve body 15 in the first embodiment. As a result, the area of the fourth pressure receiving surface 15a of the first valve body 15, which faces the valve chamber 7 and on which the fluid pressure acts in the axial direction of the valve shaft 3, is set smaller than the area of the second pressure receiving surface 16a of the second valve body 16, which faces the valve chamber 7 and on which the fluid pressure acts in the axial direction of the valve shaft 3. Along with this, in this embodiment, the inner diameter of the first valve hole 12a of the first valve seat 12 is reduced (e.g., reduced by about 20%) compared to the inner diameter of the first valve hole 12a in the first embodiment. Other configurations in this embodiment are the same as those in the first embodiment.

[0065] [Operation and Effects of the Valve Device] According to the configuration of the valve device 1 of this embodiment described above, different from the first embodiment, it has the following operations and effects. That is, in this embodiment, as shown in FIG. 3, when the first valve body 15 and the second valve body 16 are arranged at the second opening / closing position, when switching from the second opening / closing position to the first opening / closing position, the generated magnetic force that counteracts and acts on the sum of the fluid pressure acting on the first valve body 15 and the biasing force of the spring 24 (the biasing force at the start of contraction) is required for the coil 21. Here, when the first valve body 15 starts to open, the fluid pressure acting on the first valve body 15 immediately decreases, so the generated magnetic force required for the coil 21 at the start of valve opening becomes the largest. On the other hand, as shown in FIG. 4, when the first valve body 15 and the second valve body 16 are arranged at the first opening / closing position, the fluid pressure acting on the second valve body 16 is canceled out by the pressure acting on the diaphragm 5. Therefore, to maintain the state of the first opening / closing position, the generated magnetic force that counteracts and acts on the biasing force of the spring 24 (the biasing force at the end of contraction) is required for the coil 21. Here, the generated magnetic force required for the coil 21 in the state of the second opening / closing position shown in FIG. 3 is smaller than the generated magnetic force required for the coil 21 in the state of the first opening / closing position shown in FIG. 4.

[0066] Here, when switching the opening and closing positions of the first valve body 15 and the second valve body 16, the generated magnetic force required for the coil 21 is greater when the first valve body 15 and the second valve body 16 are arranged at the second opening and closing position than when they are arranged at the first opening and closing position. Therefore, as in this embodiment, by setting the area of the fourth pressure receiving surface 15a of the first valve body 15 to be smaller than the area of the second pressure receiving surface 16a of the second valve body 16, the generated magnetic force required for the coil 21 becomes smaller. In this sense, in this embodiment, compared with the first embodiment, the coil 21 can be further miniaturized, and thereby the actuator 4 can be further miniaturized.

[0067] <Third Embodiment> Next, the third embodiment will be described in detail with reference to the drawings.

[0068] [Configuration of Actuator] In this embodiment, it is different from the first embodiment in terms of the configuration of the actuator 4. FIGS. 5 and 6 schematically show a cross-sectional view of the valve device 1 of this embodiment. FIG. 5 shows a state where the valve device 1 is electrically off, and FIG. 6 shows a state where the valve device 1 is electrically on. In the off state shown in FIG. 5, the first valve body 15 and the second valve body 16 are arranged at the first opening and closing position, and in the on state shown in FIG. 6, the first valve body 15 and the second valve body 16 are arranged at the second opening and closing position.

[0069] That is, in this embodiment, it is mainly different from the first embodiment in terms of the arrangement of the fixed core 22 and the movable core 23 with respect to the spring 24. In FIGS. 5 and 6, the fixed core 22 having the recess 22a is arranged with its recess 22a facing upward inside the lower part of the coil 21. Further, the movable core 23 having a substantially cylindrical shape is arranged to face coaxially and reciprocally inside the upper part of the coil 21 opposite to the fixed core 22. Also, the other end 3b of the valve shaft 3 passing through the diaphragm 5 passes through the fixed core 22 and is connected to the movable core 23. And the spring 24 is provided between the fixed core 22 and the movable core 23 in a form that encloses the other end 3b of the valve shaft 3 at the recess 22a of the fixed core 22. Further, in this embodiment, in accordance with the change in the arrangement of the fixed core 22 and the movable core 23, the pressure derivation hole 14a of the communication hole 14 of the valve shaft 3 directly opens into the diaphragm chamber 6 on the outer periphery of the valve shaft 3.

[0070] And as shown in FIG. 5, when the valve device 1 is electrically turned off, the generation of magnetic force in the coil 21 stops, and the fixed core 22 does not axially attract the movable core 23. Therefore, the movable core 23 is pushed upward together with the valve shaft 3 by the biasing force of the spring 24. As a result, the first valve body 15 opens the first valve hole 12a, and the second valve body 16 is arranged at the first opening / closing position where the second valve hole 13a is closed. Also, as shown in FIG. 6, when the valve device 1 is electrically turned on, the fixed core 22 axially attracts the movable core 23 due to the magnetic force generated by the coil 21. Therefore, the movable core 23 is pushed downward together with the valve shaft 3 against the biasing force of the spring 24. As a result, the first valve body 15 closes the first valve hole 12a, and the second valve body 16 is arranged at the second opening / closing position where the second valve hole 13a is opened. That is, in this embodiment, the spring 24 biases the first valve body 15 and the second valve body 16 in the direction of arranging them at the first opening / closing position via the movable core 23 and the valve shaft 3.

[0071] [Operation and Effect of Valve Device] According to the configuration of the valve device 1 of this embodiment described above, unlike the first embodiment, as shown in FIG. 5, when the first valve body 15 and the second valve body 16 are arranged at the first opening / closing position, the pressure relief hole 14c is aligned with the bearing 17 and closed. At this time, the pressure of the fluid acting on the valve chamber 7 from the inlet 9 acts in a direction to bring the valve shaft 3 closer to the actuator 4 via the second valve body 16. However, the same pressure also acts on the diaphragm chamber 6 through the communication hole 14 and acts on the valve shaft 3 via the diaphragm 5 in a direction away from the actuator 4, that is, in a direction to cancel the pressure acting on the second valve body 16. Therefore, the force required to switch the first valve body 15 and the second valve body 16 from the first opening / closing position to the second opening / closing position is reduced by the amount that cancels the fluid pressure.

[0072] On the other hand, as shown in FIG. 6, when the first valve body 15 and the second valve body 16 are arranged at the second opening / closing position, the pressure relief hole 14c is opened while being separated from the bearing 17. At this time, the pressure of the fluid acting on the valve chamber 7 from the inlet 9 acts on the valve shaft 3 in a direction away from the actuator 4 via the first valve body 15. However, the pressure acting on the communication hole 14 escapes (is canceled) to the intermediate chamber 8 through the pressure relief hole 14c and does not act on the diaphragm chamber 6. Therefore, the force required to switch the first valve body 15 and the second valve body 16 from the second opening / closing position to the first opening / closing position is reduced by the amount that the fluid pressure does not act on the diaphragm chamber 6. For this reason, the biasing force of the spring 24 can be made smaller than in the first embodiment, the driving force of the actuator 4 can be reduced, and thereby the valve device 1 can function as a three-way switching valve without increasing its size.

[0073] <Fourth Embodiment> Next, the fourth embodiment will be described in detail with reference to the drawings.

[0074] [Configuration of Actuator] In this embodiment, it is different from the first and second embodiments in terms of the arrangement of the valve seats 12, 13 and the valve bodies 15, 16 in the housing 2. FIGS. 7 and 8 schematically show the valve device 1 of this embodiment in a sectional view. FIG. 7 shows the state where the valve device 1 is electrically off, and FIG. 8 shows the state where the valve device 1 is electrically on. In the off state shown in FIG. 7, the first valve body 15 and the second valve body 16 are arranged at the second opening / closing position, and in the on state shown in FIG. 8, the first valve body 15 and the second valve body 16 are arranged at the first opening / closing position.

[0075] That is, in the first and second embodiments, the first valve body 15 and the second valve body 16 are configured to move within one valve chamber 7 along with the reciprocating movement of the valve shaft 3 in the axial direction. That is, when the valve shaft 3 moves in the direction approaching the actuator 4, in the valve chamber 7, the first valve body 15 is separated from the first valve seat 12 to open the first valve hole 12a, and the second valve body 16 is seated on the second valve seat 13 to close the second valve hole 13a, and is configured to be arranged at the first opening / closing position. And when the valve shaft 3 moves in the direction away from the actuator 4, in the valve chamber 7, the first valve body 15 is seated on the first valve seat 12 to close the first valve hole 12a, and the second valve body 16 is separated from the second valve seat 13 to open the second valve hole 13a, and is configured to be arranged at the second opening / closing position.

[0076] In contrast, in this embodiment, as shown in FIGS. 7 and 8, the arrangements of the valve seats 12, 13 and the valve bodies 15, 16 in the housing 2 are different from those in the first and second embodiments as follows. That is, in this embodiment, the flow path is partitioned by the diaphragm 5 into the diaphragm chamber 6, a first valve chamber 27 in which the second valve body 16 is accommodated, an intermediate chamber 28 disposed adjacent to the first valve chamber 27, a second valve chamber 29 disposed adjacent to the intermediate chamber 28, a fluid inlet 9 provided in the intermediate chamber 28, a first fluid outlet 10 provided in the second valve chamber 29, and a second fluid outlet 11 provided in the first valve chamber 27. The valve seats 12, 13 include a first valve seat 12 having a first valve hole 12a disposed between the second valve chamber 29 and the intermediate chamber 28, and a second valve seat 13 disposed between the first valve chamber 27 and the intermediate chamber 28 and having a second valve hole 13a disposed on the same axis as the first valve hole 12a. The valve shaft 3 is disposed axially reciprocally movable on the axes of the first valve hole 12a and the second valve hole 13a, and a communication hole 14 for communicating between the intermediate chamber 28 and the diaphragm chamber 6 is provided therein. The valve bodies 15, 16 include a first valve body 15 that opens and closes the first valve hole 12a and a second valve body 16 that opens and closes the second valve hole 13a as the valve shaft 3 reciprocates axially. When the valve shaft 3 moves in a direction approaching the actuator 4, the first valve body 15 closes the first valve hole 12a, and the second valve body 16 is disposed at a first opening / closing position where the second valve hole 13a is opened. When the valve shaft 3 moves in a direction away from the actuator 4, the first valve body 15 opens the first valve hole 12a, and the second valve body 16 is disposed at a second opening / closing position where the second valve hole 13a is closed. A bearing 17 for supporting the valve shaft 3 axially reciprocally movable is provided in the first valve chamber 27. A pressure relief hole 14c communicating with the communication hole 14 corresponding to the first valve chamber 27 is provided in the valve shaft 3. The pressure relief hole 14c is configured to be closed in alignment with the bearing 17 when the first valve body 15 and the second valve body 16 are disposed at the second opening / closing position, and to be opened away from the bearing 17 when the first valve body 15 and the second valve body 16 are disposed at the first opening / closing position. That is, in this embodiment, as the valve shaft 3 reciprocates axially, the first valve body 15 is configured to move in the second valve chamber 29, and the second valve body 16 is configured to move in the first valve chamber 27.

[0077] [Operation and Effect of the Valve Device] According to the configuration of the valve device 1 of this embodiment described above, unlike the first and second embodiments, when the first valve body 15 and the second valve body 16 are disposed at the second opening / closing position, the pressure relief hole 14c is aligned with the bearing 17 and closed. At this time, the pressure of the fluid acting from the inlet 9 to the intermediate chamber 28 acts in a direction to bring the valve shaft 3 closer to the actuator 4 via the second valve body 16. However, the same pressure also acts on the diaphragm chamber 6 through the communication hole 14, and acts on the valve shaft 3 through the diaphragm 5 in a direction away from the actuator 4, that is, in a direction to cancel the pressure acting on the second valve body 16. Therefore, the force required to switch the first valve body 15 and the second valve body 16 from the second opening / closing position to the first opening / closing position is reduced by an amount that cancels the pressure of the fluid acting on the valve shaft 3 via the second valve body 16. On the other hand, when the first valve body 15 and the second valve body 16 are disposed at the first opening / closing position, the pressure relief hole 14c is opened while being separated from the bearing 17. At this time, the pressure of the fluid acting from the inlet 9 to the intermediate chamber 28 acts on the valve shaft 3 in a direction away from the actuator 4 via the first valve body 15. However, the pressure acting on the communication hole 14 escapes (is canceled) to the first valve chamber 27 through the pressure relief hole 14c and does not act on the diaphragm chamber 6. Therefore, the force required to switch the first valve body 15 and the second valve body 16 from the first opening / closing position to the second opening / closing position is reduced by an amount that the pressure of the fluid acting on the intermediate chamber 28 acts on the valve shaft 3 in a direction away from the actuator 4 via the first valve body 15. For this reason, the driving force of the actuator 4 can be reduced, and thereby the valve device 1 can function as a three-way switching valve without increasing the size of the valve device 1.

[0078] <Another Embodiment> Note that the disclosed technology is not limited to the above-described embodiments, and a part of the configuration can be appropriately changed and implemented without departing from the spirit of the disclosed technology.

[0079] (1) In the first embodiment, when the inner diameter of the pressure derivation hole 14a is larger than the inner diameter of the pressure introduction hole 14b, the inner diameter of the pressure relief hole 14c is set to be larger than the inner diameter of the pressure introduction hole 14b. On the other hand, when the inner diameter of the pressure derivation hole 14a is smaller than the inner diameter of the pressure introduction hole 14b, the inner diameter of the pressure relief hole 14c can also be set to be larger than the inner diameter of the pressure derivation hole 14a. Also in this case, the same operations and effects as those of the first embodiment can be obtained.

[0080] (2) In the second embodiment, in the configuration of the first embodiment, by reducing the maximum outer diameter of the first valve body 15 to be smaller than the maximum outer diameter of the first valve body 15 in the first embodiment, the area of the fourth pressure receiving surface 15a of the first valve body 15, which faces the valve chamber 7 and on which the fluid pressure acts in the axial direction of the valve shaft 3, is set to be smaller than the area of the second pressure receiving surface 16a of the second valve body 16, which faces the valve chamber 7 and on which the fluid pressure acts in the axial direction of the valve shaft 3. On the other hand, in the configuration of the first embodiment, by expanding the maximum outer diameter of the second valve body 16 to be larger than the maximum outer diameter of the second valve body 16 in the first embodiment, the area of the fourth pressure receiving surface 15a of the first valve body 15, which faces the valve chamber 7 and on which the fluid pressure acts in the axial direction of the valve shaft 3, can also be set to be smaller than the area of the second pressure receiving surface 16a of the second valve body 16, which faces the valve chamber 7 and on which the fluid pressure acts in the axial direction of the valve shaft 3. In this case, without increasing the generated magnetic force required for the coil 21, that is, without increasing the size of the coil 21, the maximum outer diameter of the second valve body 16 can be increased with respect to the configuration of the first embodiment.

Industrial Applicability

[0081] This disclosed technology can be used, for example, in a valve device provided in an engine to control the flow of fluids such as EGR gas and intake air.

Explanation of Reference Numerals

[0082] 1 Valve device 2 Housing 3 Valve shaft 3a One end portion 3b The other end portion 4 Actuator 5 Diaphragm 6 Diaphragm chamber (flow path) 7 Valve chamber (flow path) 8 Intermediate chamber (flow path) 9 Inlet (flow path) 10 First outlet (flow path) 11 Second outlet (flow path) 12 First valve seat 12a First valve hole 13 Second valve seat 13a Second valve hole 14 Communication hole 14a Pressure derivation hole 14b Pressure introduction hole 14c Pressure relief hole 15 First valve body 16 Second valve body 17 Bearing 21 Coil 22 Fixed iron core 23 Movable iron core 24 Spring (biasing member) 27 First valve chamber 28 Intermediate chamber 29 Second valve chamber

Claims

1. A housing including a fluid flow path, A valve seat provided in the flow path and having a valve hole, A valve body provided in the flow path so as to be seatable on the valve seat to open and close the valve hole, A valve shaft provided in the housing so as to be axially movable, including one end and the other end, with the valve body provided at the one end, An actuator connected to the housing, with the other end of the valve shaft being drivingly connected to reciprocate the valve shaft in the axial direction, A diaphragm disposed between the housing and the actuator and through which the valve shaft passes, A diaphragm chamber provided between the housing and the actuator, partitioned from the housing side by the diaphragm, and in which the other end of the valve shaft is disposed In a valve device comprising: The flow path includes a valve chamber in which the valve body is accommodated, an intermediate chamber partitioned from the diaphragm chamber by the diaphragm and disposed between the valve chamber and the diaphragm chamber, an inlet and a first outlet of the fluid provided in the valve chamber, and a second outlet of the fluid provided in the intermediate chamber, The valve seat includes a first valve seat having a first valve hole disposed corresponding to the first outlet, and a second valve seat disposed between the valve chamber and the intermediate chamber and having a second valve hole disposed on the same axis as the first valve hole, The valve shaft is disposed axially reciprocally movable on the axis of the first valve hole and the second valve hole, and a communication hole for communicating between the valve chamber and the diaphragm chamber is provided therein, The valve body includes a first valve body for opening and closing the first valve hole and a second valve body for opening and closing the second valve hole as the valve shaft reciprocates in the axial direction. When the valve shaft moves in a direction approaching the actuator, the first valve body opens the first valve hole and the second valve body closes the second valve hole, and it is arranged at a first opening and closing position. When the valve shaft moves in a direction away from the actuator, the first valve body closes the first valve hole and the second valve body opens the second valve hole, and it is configured to be arranged at a second opening and closing position, A bearing for supporting the valve shaft to be axially reciprocally movable is provided in the intermediate chamber, The valve shaft is provided with a pressure relief hole communicating with the communication hole corresponding to the intermediate chamber. The pressure relief hole is configured to be closed in alignment with the bearing when the first valve body and the second valve body are disposed at the first opening / closing position, and to be opened while being separated from the bearing when the first valve body and the second valve body are disposed at the second opening / closing position. A valve device characterized by the above. **Claim 2** A housing including a fluid flow path, A valve seat provided in the flow path and having a valve hole, A valve body provided in the flow path and seatable on the valve seat to open and close the valve hole, A valve shaft provided in the housing so as to be axially movable, including one end portion and the other end portion, with the valve body provided at the one end portion, An actuator connected to the housing and having the other end portion of the valve shaft drivingly connected thereto for reciprocating the valve shaft in the axial direction, A diaphragm disposed between the housing and the actuator and through which the valve shaft penetrates, A diaphragm chamber provided between the housing and the actuator, partitioned by the diaphragm from the side of the housing, and in which the other end portion of the valve shaft is disposed In a valve device comprising: The flow path is partitioned by the diaphragm from the diaphragm chamber, and includes a first valve chamber in which the valve body is accommodated, an intermediate chamber disposed adjacent to the first valve chamber, a second valve chamber disposed adjacent to the intermediate chamber, an inlet of the fluid provided in the intermediate chamber, a first outlet of the fluid provided in the second valve chamber, and a second outlet of the fluid provided in the first valve chamber. The valve seat includes a first valve seat having a first valve hole disposed between the second valve chamber and the intermediate chamber, and a second valve seat disposed between the first valve chamber and the intermediate chamber and having a second valve hole disposed on the same axis as the first valve hole. The valve shaft is disposed axially reciprocally movable on the axis of the first valve hole and the second valve hole, and a communication hole communicating between the intermediate chamber and the diaphragm chamber is provided inside thereof. The valve body includes a first valve body that opens and closes the first valve hole and a second valve body that opens and closes the second valve hole as the valve shaft reciprocates in the axial direction. When the valve shaft moves in a direction approaching the actuator, the first valve body closes the first valve hole, and the second valve body is disposed at a first opening / closing position where the second valve hole is opened. When the valve shaft moves in a direction away from the actuator, the first valve body opens the first valve hole, and the second valve body is disposed at a second opening / closing position where the second valve hole is closed. A bearing for supporting the valve shaft so as to be reciprocable in the axial direction is provided in the first valve chamber. A pressure relief hole communicating with the communication hole is provided in the valve shaft corresponding to the first valve chamber. The pressure relief hole is configured to be closed in alignment with the bearing when the first valve body and the second valve body are disposed at the second opening / closing position, and to be opened away from the bearing when the first valve body and the second valve body are disposed at the first opening / closing position. A valve device characterized by the above.

3. In the valve device according to claim 1 or 2, A pressure derivation hole for deriving the pressure of the fluid acting on the communication hole to the diaphragm chamber and a pressure introduction hole for introducing the pressure of the fluid in the valve chamber to the communication hole are formed in the valve shaft. When the inner diameter of the pressure derivation hole is larger than the inner diameter of the pressure introduction hole, the inner diameter of the pressure relief hole is set larger than the inner diameter of the pressure introduction hole. A valve device characterized by the above.

4. In the valve device according to claim 1 or 2, A pressure derivation hole for deriving the pressure of the fluid acting on the communication hole to the diaphragm chamber and a pressure introduction hole for introducing the pressure of the fluid in the valve chamber to the communication hole are formed in the valve shaft. When the inner diameter of the pressure derivation hole is smaller than the inner diameter of the pressure introduction hole, the inner diameter of the pressure relief hole is set larger than the inner diameter of the pressure derivation hole. A valve device characterized by the above.

5. In the valve device according to claim 1 or 2, The actuator includes: A coil that generates a magnetic force when energized; A fixed iron core with the coil disposed outside; A movable iron core that is coaxially opposed to the fixed iron core and is reciprocable and is connected to the valve shaft; and A biasing member for biasing the movable iron core in a predetermined direction. In order to reciprocate the valve shaft in the axial direction, the fixed iron core is configured to attract the movable iron core in the axial direction by the magnetic force generated by the coil. A valve device characterized by the following.

6. In the valve device according to claim 3, the actuator includes a coil that generates magnetic force when energized, a fixed core with the coil disposed outside thereof, a movable core that is coaxially opposed to the fixed core and is reciprocally movable, and is connected to the valve shaft, and a biasing member for biasing the movable core in a predetermined direction and is configured such that the fixed core attracts the movable core in the axial direction by the magnetic force generated by the coil in order to reciprocate the valve shaft in the axial direction. A valve device characterized by the following.

7. In the valve device according to claim 4, the actuator includes a coil that generates magnetic force when energized, a fixed core with the coil disposed outside thereof, a movable core that is coaxially opposed to the fixed core and is reciprocally movable, and is connected to the valve shaft, and a biasing member for biasing the movable core in a predetermined direction and is configured such that the fixed core attracts the movable core in the axial direction by the magnetic force generated by the coil in order to reciprocate the valve shaft in the axial direction. A valve device characterized by the following.

8. In the valve device according to claim 5, the biasing member is a spring that biases the movable core in a direction away from the fixed core. A valve device characterized by the following.

9. In the valve device according to claim 6, the biasing member is a spring that biases the movable core in a direction away from the fixed core. A valve device characterized by the following.

10. In the valve device according to claim 7, the biasing member is a spring that biases the movable core in a direction away from the fixed core. A valve device characterized by the following.

11. In the valve device according to claim 8, the area of the first pressure-receiving surface of the diaphragm, on which the fluid pressure acts in the axial direction of the valve shaft facing the diaphragm chamber, and the area of the second pressure-receiving surface of the second valve body, on which the fluid pressure acts in the axial direction of the valve shaft facing the valve chamber, are set to be substantially the same. A valve device characterized by the following.

12. In the valve device according to claim 8, the area of the fourth pressure-receiving surface of the first valve body, on which the fluid pressure acts in the axial direction of the valve shaft facing the valve chamber, is set to be smaller than the area of the second pressure-receiving surface of the second valve body, on which the fluid pressure acts in the axial direction of the valve shaft facing the valve chamber. A valve device characterized by the following.

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