Air motor and valve device

Abstract

The present invention provides an air motor and valve device that are miniaturized and lightweight, and that can move a piston in either direction even if the supply of gas or power is interrupted. [Solution] The valve device comprises a cylinder rod 70 attached to a valve body 30, a cylinder body 51 having a cylinder chamber 54, a piston 60 connected to the cylinder rod 70 and provided to move the cylinder chamber 54 in the axial direction of the cylinder rod 70, a first chamber 56 isolated from the cylinder chamber 54, a pressure adjusting means for adjusting the pressure of the gas supplied from a gas supply source, and a control unit for controlling the operation of the pressure adjusting means. Under the control of the control unit, the pressure adjusting means adjusts the pressure of the first chamber, and under the control of the control unit, it includes a switching means for switching the communication between the first chamber 56 and the second chamber 57, or the communication between the first chamber 56 and the third chamber 58.

Description

TECHNICAL FIELD

[0001] The present invention relates to an air motor that operates by gas pressure, and a valve device including the air motor and a valve body.

BACKGROUND ART

[0002] An air cylinder (also referred to as an air motor) that operates a valve body for opening and closing a flow path by gas pressure is known (see, for example, Patent Document 1).

[0003] The air motor includes a cylinder, a piston disposed inside the cylinder, and a biasing means such as a coil spring that biases the piston in one direction. The gas pressure moves the piston against the biasing force of the biasing means in the other direction opposite to the one direction, and the biasing force of the coil spring, or the biasing force in addition to the gas pressure moves the piston in the one direction, thereby causing the piston to reciprocate between the one direction and the other direction.

[0004] In such an air motor, when the power supply to a gas supply source such as a pump represented by a compressor that supplies gas or a control unit that controls the gas supply source is cut off, or when gas supplied to the cylinder can no longer be supplied at a predetermined pressure due to a failure of the gas supply source, breakage of piping, or the like, the piston can be moved in one direction by the biasing force of the biasing means. For this reason, when the air motor is used to open and close the valve element of the valve body, airless close that closes the valve or airless open that opens the valve by the biasing force of the biasing means is possible when power cutoff, gas leakage, or the like occurs.

[0005] Further, there has been proposed an air motor that reciprocates a piston only by gas supply without using a biasing means such as a coil spring (see, for example, Patent Documents 2 and 3).

PRIOR ART DOCUMENTS

PATENT DOCUMENTS

[0006] [Patent Document 1] Japanese Patent Application Publication No. 09-144903 [Patent Document 2] Japanese Utility Model Publication No. 53-041733 [Patent Document 3] Japanese Patent Publication No. 2007-120522 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, in an air motor that reciprocates a piston simply by supplying gas without using a biasing mechanism, there is a problem that the piston cannot be moved by the biasing mechanism if the power supply is cut off or the gas leaks, and therefore the valve cannot be closed or opened.

[0008] Furthermore, in air motors that use biasing means, in order to implement the required biasing force, it is necessary to implement biasing means such as coil springs with elasticity and a considerable mass, and a container structure with a volume that can house these biasing means, which leads to the problem of increased size and weight.

[0009] In view of these circumstances, the present invention aims to provide an air motor and valve device that are miniaturized and lightweight, and that can move a piston in either direction even if the supply of gas or power is interrupted. [Means for solving the problem]

[0010] An aspect of the present invention that solves the above problems is an air motor comprising: a cylinder rod attached to the valve body of a valve device; a cylinder body having a cylinder chamber; a piston connected to the cylinder rod and provided to move the cylinder chamber in the axial direction of the cylinder rod; a first chamber isolated from the cylinder chamber; a pressure adjusting means for adjusting the pressure of gas supplied from a gas supply source; and a control unit for controlling the operation of the pressure adjusting means, wherein the cylinder chamber comprises a second chamber and a third chamber partitioned by the piston, and the piston is moved by adjusting the pressure of the gas inside the second chamber and the third chamber by the pressure adjusting means under the control of the control unit, wherein the pressure adjusting means adjusts the pressure of the first chamber under the control of the control unit, and a switching means for switching the communication between the first chamber and the second chamber or the communication between the first chamber and the third chamber under the control of the control unit.

[0011] In this configuration, when the power supply to a gas supply source such as a pump that supplies gas, or a control unit that controls the gas supply source, is cut off, or when the gas supplied to the cylinder cannot be supplied at a predetermined pressure due to a failure of the gas supply source or damage to the piping, the gas in the first chamber can be supplied to the second or third chamber to move the piston. Furthermore, since there is no need to use a biasing means such as a coil spring to move the piston when power is not supplied, the implementation of a biasing means such as a coil spring with elasticity and a considerable mass, and a container structure with a volume to house this biasing means, which are necessary to implement the required biasing force, become unnecessary, allowing for miniaturization and weight reduction.

[0012] Here, it is preferable that the switching means moves the piston by adjusting the pressure in the second and third chambers when the first and second chambers are not in communication and the first and third chambers are not in communication, and that the switching means moves the piston by adjusting the pressure in the second and third chambers when the first and second chambers are not in communication, and that the switching means moves the piston without adjusting the pressure in the second and third chambers by connecting the first and second chambers and supplying the gas from the first chamber to the second chamber, or supplying the gas from the second chamber to the first chamber. According to this, even without adjusting the pressure by the pressure adjusting means, the piston can be moved to expand the second chamber by supplying the gas from the first chamber to the second chamber, and the piston can be moved to expand the third chamber by supplying the gas from the second chamber to the first chamber.

[0013] Furthermore, it is preferable that the piston is moved by the pressure adjustment means adjusting the pressure in the second and third chambers when the switching means is in a state where the first and second chambers are not in communication, and when the first and third chambers are not in communication, and the switching means is in a state where the first and third chambers are not in communication, and the piston is moved by the pressure adjustment means adjusting the pressure in the second and third chambers. It is preferable that the piston is moved without the pressure adjustment means adjusting the pressure in the second and third chambers by connecting the first and third chambers and supplying the gas from the first chamber to the third chamber, or supplying the gas from the third chamber to the first chamber. According to this, even without pressure adjustment by the pressure adjustment means, the piston can be moved to expand the third chamber by supplying the gas from the first chamber to the third chamber, and the piston can be moved to expand the second chamber by supplying the gas from the third chamber to the first chamber.

[0014] Furthermore, it is preferable that the switching means includes a switching valve that opens when power is not supplied. This allows the switching means to open the valve and connect the first chamber and the second chamber, or the first chamber and the third chamber, without using a power source.

[0015] Furthermore, the pressure regulating means preferably includes a gas supply source for pressurizing or drawing in gas, and a first supply valve connected between the gas supply source and the first chamber, wherein the first supply valve is closed when power is not supplied. This allows the first chamber to be sealed by closing the first supply valve when the power is cut off.

[0016] Furthermore, it is preferable that the system includes pressure detection means for detecting the pressure of the gas supplied to the second and third chambers, and that the control means switches the switching means based on the pressure of at least one of the gases supplied to the second and third chambers detected by the pressure detection means. This allows the piston to move even in the event of a gas supply failure.

[0017] Furthermore, another aspect of the present invention is a valve device comprising an air motor as described in any one of the above aspects, a valve body having a valve element attached to the cylinder rod of the air motor, and a flow path that is opened and closed by the valve element.

[0018] According to this, in the event of an abnormality, gas from the first chamber can be supplied to the second or third chamber to move the piston and cause the valve device to close or open. [Effects of the Invention]

[0019] The present invention can move the valve element of the valve device by moving the piston by supplying the gas in the first chamber to the second chamber or the third chamber in the event of an abnormality, such as when the power to the gas supply source such as a pump represented by a compressor for supplying gas or the control unit for controlling the gas supply source is cut off, or when the gas supplied to the cylinder cannot be supplied at a predetermined pressure due to a failure of the gas supply source, breakage of piping, or the like. Further, since it is not necessary to use a biasing means such as a coil spring for moving the piston when power is not supplied, the mounting of a biasing means such as a coil spring having a considerable mass with elasticity to provide the required biasing force, and a container structure having a volume capable of accommodating this biasing means are no longer required, whereby size reduction and weight reduction can be achieved. [Brief Description of the Drawings]

[0020] [Figure 1] It is a diagram showing a schematic configuration of a valve device according to Embodiment 1 of the present invention. [Figure 2] It is a cross-sectional view of the air motor and the valve main body according to Embodiment 1 of the present invention. [Figure 3] It is a cross-sectional view of the air motor and the valve main body according to Embodiment 1 of the present invention. [Figure 4] It is a diagram for explaining the operation of the valve device according to Embodiment 1 of the present invention. [Figure 5] It is a diagram showing a schematic configuration of a valve device according to Embodiment 2 of the present invention. [Figure 6] It is a diagram for explaining the operation of the valve device according to Embodiment 2 of the present invention. [Mode for Carrying Out the Invention]

[0021] Hereinafter, the present invention will be described in detail based on embodiments.

[0022] (Embodiment 1) Figure 1 is a cross-sectional view of the main parts showing the schematic configuration of the valve device 1 according to Embodiment 1 of the present invention in the closed state. Figure 2 is a cross-sectional view showing the air motor 3 and valve body 2 in the closed state. Figure 3 is a cross-sectional view showing the air motor 3 and valve body 2 in the open state. Note that in Figure 2, the position of the piston 60 when the valve body 2 is open is indicated by a dotted line. Also, in Figure 3, the position of the piston 60 when the valve body 2 is closed is indicated by a dotted line.

[0023] As shown in the figure, the valve device 1 of this embodiment comprises a valve body 2, an air motor 3, and a valve head 4.

[0024] <Valve body> As shown in Figures 2 and 3, the valve body 2 comprises a flow path member 10, a fixing member 20, a valve body 30, and a diaphragm 40.

[0025] The flow path member 10 is a so-called valve body with a flow path 11 provided inside. The flow path 11 comprises a valve chamber 12, an inlet 13, and an outlet 14.

[0026] The valve chamber 12 has a valve opening 12a in the portion that communicates with the inlet 13. The valve opening 12a has a tapered shape, with its inner circumferential surface inclined so that the inner diameter gradually decreases toward the inlet 13. This tapered inner circumferential surface of the valve opening 12a forms the valve seat 15.

[0027] The inlet 13 opens to the lower side in Figure 1, and the outlet 14 opens to the left side in Figure 1. In other words, the liquid flowing in from the inlet 13 is bent at approximately 90 degrees through the valve chamber 12 and flows out from the outlet 14. Piping (not shown) is connected to each of these inlet 13 and outlet 14.

[0028] On the side of the flow path member 10 opposite the inlet 13, there is an opening 16 that connects the valve chamber 12 to the outside, and the opening 16 is closed by a fixing member 20.

[0029] The valve body 30 comprises a valve body portion 31, a valve stem portion 32, and a contact portion 33.

[0030] The valve body 31 consists of a circular plate-shaped member. A contact portion 33 made of an elastic material such as rubber or elastomer is fixed to the portion of the valve body 31 facing the valve seat 15. The contact portion 33 is continuously provided circumferentially on the surface of the valve body 31 facing the valve seat 15, and in the radial direction of the valve stem 32, the thickness of the contact portion 33 gradually decreases toward the valve seat 15. In other words, the radial cross-sectional shape of the contact portion 33 is approximately triangular, with the vertex of the triangle facing the valve seat.

[0031] The valve stem portion 32 is fixed at one end to the valve body portion 31. In this embodiment, the valve stem portion 32 and the valve body portion 31 are made of a single integrated member. Of course, the valve body portion 31 and the valve stem portion 32 may be fixed as separate components. The valve stem portion 32 has a mounting portion 34. The mounting portion 34 is coaxial with the valve stem portion 32 and protrudes from the valve stem portion 32 toward the joint rod 5 side. A screw groove (not shown) is cut into the side surface of the mounting portion 34. Furthermore, the valve stem portion 32 has a stepped portion 35 on the mounting portion 34 side, which is a reduced diameter portion.

[0032] The diaphragm 40 is a member made of a flexible resin and has a first insertion hole 41 in its center. The back plate 42 also has a third insertion hole 43 that opens in a stepped manner in its center. The narrower part of the third insertion hole 43 is called the third insertion hole 43a, and the wider part is called the third insertion hole 43b. The joint rod 5 is fitted into the third insertion hole 43b of the back plate 42.

[0033] The mounting portion 34 is fastened to the joint rod 5 by being inserted through the first insertion hole 41 and the third insertion hole 43 and screwed into the screw hole 5a provided at one end of the joint rod 5. Furthermore, when the mounting portion 34 is screwed into the screw hole 5a of the joint rod 5, the edge of the first insertion hole 41 of the diaphragm 40 is clamped between the stepped portion 35 and the back plate 42. In addition, the peripheral edge of the diaphragm 40 is clamped between the fixing member 20 and the projection 17 provided on the flow path member 10. The clamped diaphragm 40 seals the space between the opening 16 of the valve chamber 12 and the valve stem portion 32. In other words, the diaphragm 40 prevents the liquid inside the valve chamber 12 from leaking out from the opening 16 side. Although not specifically shown in the figures, it is preferable to provide O-rings between the stepped portion 35 and the edge of the first insertion hole 41 of the diaphragm 40, and between the fixing member 20 and the projection 17, to prevent liquid from leaking out.

[0034] The fixing member 20 comprises a second insertion hole 21 through which the joint rod 5 is inserted, and a back plate housing portion 22 that communicates with the second insertion hole 21 and has a concave shape capable of accommodating the back plate 42. The fixing member 20 is fixed to the opening 16 side of the flow path member 10 by a clamp 23 with the joint rod 5 inserted through the second insertion hole 21 and the back plate 42 housed in the back plate housing portion 22.

[0035] Furthermore, the fixing member 20 has a fixing portion 25 having a connection space 24 for connecting the joint rod 5 and the cylinder rod 70 of the air motor 3. The fixing portion 25 has a fixing opening 26 for communicating a part of the side surface of the connection space 24 to the outside. A fourth insertion hole 27 for inserting the cylinder rod 70 is provided in the side wall of this fixing portion 25 on the air motor 3 side.

[0036] The fixing member 20 has a fixing portion 25 that is fixed to the cap 52 of the air motor 3 by fixing screws 28. In this embodiment, the fixing member 20 and the cap 52 are fixed to each other by fixing screws 28, but the embodiment is not limited to this, and the fixing member 20 and the cap 52 may be a single, integrally provided member.

[0037] The valve body 30 moves up and down in Figures 2 and 3 by the drive of an air motor 3 connected via a joint rod 5. As shown in Figure 2, when the valve body 30 is in the downward position in Figure 2, the valve body 30 closes the valve opening 12a with its contact portion 33 in contact with the valve seat 15. This state is called the closed valve state. In the closed valve state, the inlet portion 13 and the outlet portion 14 are separated by the valve body 30, and the outflow of liquid flowing in from the inlet portion 13 to the outlet portion 14 is stopped.

[0038] As shown in Figure 3, when the valve body 30 is moved upward in Figure 3, the valve body 30 opens the valve port 12a with the contact portion 33 separated from the valve seat 15. This state is called the open valve state. In the open valve state, the liquid that flows in from the inlet portion 13 flows out from the outlet portion 14.

[0039] As the valve body 30 moves in both the closed and open states, the diaphragm 40 undergoes flexible deformation.

[0040] <Air Motor> The air motor 3 comprises a cylinder 50, a piston 60, and a cylinder rod 70.

[0041] The cylinder 50 comprises a cylinder body 51, two caps 52, and one partition wall 53.

[0042] The cylinder body 51 is cylindrical in shape, having a cylinder chamber 54 inside; in this embodiment, it is cylindrical. However, the cylinder body 51 is not limited to a cylindrical shape and may be elliptical or the like. Such a cylinder body 51 is made of metal, resin, or fiber-reinforced plastic (FRP).

[0043] The two caps 52 close the respective openings at both ends of the cylinder body 51. In this embodiment, in Figures 2 and 3, the cap 52 that closes the upper opening of the cylinder body 51 is referred to as the first cap 52A, and the cap 52 that closes the lower opening of the cylinder body 51, that is, the opening on the valve body 2 side, is referred to as the second cap 52B. Hereafter, when the first cap 52A and the second cap 52B are not distinguished, they will be referred to as cap 52. The first cap 52A and the second cap 52B are the same cap 52, but are used in reverse. Therefore, there is no need to manufacture the first cap 52A and the second cap 52B separately or manage inventory, which reduces costs.

[0044] Such a cap 52 is made of a plate-like member having a circular shape. A step 52a is provided at the end of the cap 52, into which the cylinder body 51 is fitted.

[0045] Furthermore, at least two screw holes 52b are provided on the side of the cap 52 opposite to the cylinder chamber 54. The fixing member 20 is fixed to the screw holes 52b of the second cap 52B via fixing screws 28. The screw holes 52b of the first cap 52A are used to fix the valve head 4 (see Figure 1) with fixing screws.

[0046] Furthermore, a fifth insertion hole 55 is provided in the center of the cap 52. The cylinder rod 70 is inserted through the fifth insertion hole 55. It is preferable to provide a bush or O-ring (not shown) on the inner surface of the fifth insertion hole 55 of the cap 52.

[0047] The partition wall 53 is provided inside the cylinder body 51 and divides the space between the first cap 52A and the partition wall 53, and the space between the second cap 52B and the partition wall 53. In this embodiment, the space between the first cap 52A and the partition wall 53 is referred to as the first chamber 56. The piston 60 is positioned in the space between the second cap 52B and the partition wall 53 so as to be able to reciprocate in the axial direction of the cylinder rod 70. In other words, the space between the second cap 52B and the partition wall 53 is divided by the piston 60. The space between this partition wall 53 and the piston 60 is referred to as the second chamber 57, and the space between the second cap 52B and the piston 60 is referred to as the third chamber 58. In other words, the volume of the second chamber 57 and the third chamber 58 increases or decreases depending on the position of the piston 60.

[0048] Furthermore, a sixth insertion hole 59 is provided in the partition wall 53. The cylinder rod 70 is inserted through the sixth insertion hole 59. It is preferable to provide a bush or O-ring (not shown) on the inner surface of the partition wall 53.

[0049] The piston 60 is made of a circular plate-shaped member, and a fixing hole 61 is provided through the center of the piston 60, which is coaxial with the fifth insertion hole 55 and the sixth insertion hole 59. The cylinder rod 70 is inserted through this fixing hole 61 of the piston 60 and fixed in place. In other words, the cylinder rod 70 is inserted through the sixth insertion hole 59 of the partition wall 53 and the fifth insertion hole 55 of the cap 52, with both ends positioned outside the two caps 52.

[0050] Furthermore, the outer circumferential surface of the piston 60 is provided with a retaining portion 62 having a concave shape that opens onto the outer circumferential surface, and an O-ring 63 is held inside the retaining portion 62. The piston 60 moves while the O-ring 63 held in the retaining portion 62 slides against the inner circumferential surface of the cylinder body 51, thereby maintaining airtightness between the second chamber 57 and the third chamber 58 separated by the piston 60.

[0051] In this embodiment, the air motor 3 does not have a biasing means such as a coil spring that biases the piston 60 in the axial direction of the cylinder rod 70. In other words, the piston 60 operates solely by the pressure difference between the gas in the second chamber 57 and the gas in the third chamber 58.

[0052] Furthermore, the cylinder body 51 is provided with a first flow channel opening 81, a second flow channel opening 82, and a third flow channel opening 83.

[0053] The first flow channel opening 81 is provided to connect the first chamber 56 to the outside. The second flow channel opening 82 is provided to connect the second chamber 57 to the outside. The third flow channel opening 83 is provided to connect the third chamber 58 to the outside. Each of the first flow channel openings 81, 82, and 83 is fitted with a connecting part 85 for connecting pipes 86A to 86C.

[0054] The second flow port 82 and the third flow port 83 are positioned so as not to be blocked by the piston 60 when the piston 60 moves. In this embodiment, a first projection 52c with a small outer diameter is provided on the surface of the cap 52 facing the cylinder chamber 54. The third flow port 83 is positioned opposite the first projection 52c so that the third flow port 83 is not blocked by the piston 60 when the piston 60 moves toward the second cap 52B. In this embodiment, as shown in Figure 2, the movement of the piston 60 toward the valve body 2 is restricted because the valve body 30 contacts the valve seat 15 before the piston 60 contacts the second cap 52B.

[0055] Furthermore, the piston 60 is provided with a second projection 64 having a smaller outer diameter on the side facing the partition wall 53. When the piston 60 moves toward the partition wall 53, its movement is restricted when the second projection 64 comes into contact with the partition wall 53. Therefore, the second flow channel opening 82 is positioned so that it faces the second projection 64 when the second projection 64 comes into contact with the partition wall 53, preventing the second flow channel opening 82 from being blocked by the piston 60. In this embodiment, the movement of the piston 60 toward the partition wall 53 is restricted when the back plate 42 comes into contact with the back plate housing 22 before the piston 60 comes into contact with the partition wall 53.

[0056] Furthermore, the air motor 3 includes pressure adjustment means for adjusting the pressure of the gas supplied from the pressure supply source, switching means for switching between communication between the first chamber 56 and the second chamber 57 and communication between the first chamber 56 and the third chamber 58, and a control unit 100 for controlling the operation of the pressure adjustment means and the switching means.

[0057] The pressure regulating means includes three pipes 86A to 86C provided for the first flow port 81, the second flow port 82, and the third flow port 83, respectively; three pumps 87A to 87C, which are the pressure supply sources of this embodiment; and three valves mounted on the valve head 4, which are the first supply valve 91 to the third supply valve 93.

[0058] More specifically, one end of the pipe 86A is connected to the connection part 85 of the first flow channel port 81, and the other end is connected to the pump 87A. In this embodiment, the pump 87A is an air compressor, or so-called compressor, that supplies compressed air to the first chamber 56 via the pipe 86A. Note that the gas supply source is not limited to the pump 87A, which is represented by the compressor, but may also be a cylinder in which compressed air is stored. The first supply valve 91 is provided in the middle of the pipe 86A and supplies or stops compressed air from the pump 87A to the first chamber 56.

[0059] One end of the piping 86B is connected to the connection part 85 of the second flow channel port 82, and the other end is connected to the pump 87B. In this embodiment, the pump 87B is an air compressor that supplies compressed air to the second chamber 57 via the piping 86B, similar to the pump 87A. The second supply valve 92 is provided in the middle of the piping 86B to supply or stop air from the pump 87B to the second chamber 57.

[0060] One end of the pipe 86C is connected to the connection part 85 of the third flow channel port 83, and the other end is connected to the pump 87C. In this embodiment, the pump 87C is an air compressor that supplies compressed air to the third chamber 58 via the pipe 86C, similar to the pump 87A. The third supply valve 93 is provided in the middle of the pipe 86C to supply or stop air from the pump 87C to the third chamber 58.

[0061] The control unit 100 is mounted on the valve head 4. The control unit 100 also controls the operation of the pressure adjustment means to adjust the pressure inside the first chamber 56 to the third chamber 58. In this embodiment, the control unit 100 controls the opening and closing of the first supply valve 91, the second supply valve 92, and the third supply valve 93 to adjust the pressure inside the first chamber 56 to the third chamber 58 by controlling the supply or stopping of compressed air to the first chamber 56, the second chamber 57, and the third chamber 58 by the pumps 87A to 87C. In other words, the first supply valve 91, the second supply valve 92, and the third supply valve 93 are solenoid valves or motorized valves that are operated by the control unit 100. Incidentally, a solenoid valve is a valve device that is operated by an actuator using an electromagnet, and a motorized valve is a valve device that is operated by an electric motor.

[0062] The control unit 100 may adjust the pressure of the gas supplied to the first chamber 56 to the third chamber 58 by adjusting the output of pumps 87A to 87C. Alternatively, if the first supply valves 91 to the third supply valves 93 have a function to adjust their opening degree, the control unit 100 may adjust the pressure of the gas supplied to the first chamber 56 to the third chamber 58 by adjusting the opening degree of these valves. If the first supply valves 91 to the third supply valves 93 do not have a function to adjust the pressure, the control unit 100 may provide a separate pressure adjustment valve and adjust the opening degree of the pressure adjustment valve.

[0063] Furthermore, the gas supplied by pumps 87A to 87C to the first chamber 56 to the third chamber 58 is not limited to air, but may be an inert gas such as nitrogen, or dry air with low humidity, etc.

[0064] Such an air motor 3 performs different operations under normal conditions and abnormal conditions. Here, "normal operation" refers to the state in which power is supplied to the air motor 3, and there are no malfunctions in pumps 87A to 87C, damage to piping 86A to 86C, or malfunctions in the first supply valve 91 to the third supply valve 93, and the system is in its normal operating condition. The opening and closing of valve device 1 by the operation of the air motor 3 under normal conditions will be described in detail later.

[0065] On the other hand, an abnormal situation refers to a situation where air cannot be supplied at the specified pressure due to a power outage, a malfunction of pumps 87A to 87C, damage to piping 86A to 86C, a malfunction of the first supply valve 91 to the third supply valve 93, etc.

[0066] In this embodiment, the first supply valve 91 automatically closes in the event of an abnormality, preventing the gas in the first chamber 56 from being discharged to the outside. In other words, the pressure in the first chamber 56 is maintained when the first supply valve 91 closes if air at the desired pressure is no longer supplied to the first chamber 56 due to a power outage, a failure of the pump 87A, damage to the piping 86A, etc. In short, the first supply valve 91 in this embodiment is a normally closed valve device that can be controlled to open and close under normal conditions, and automatically closes in the event of an abnormality using a conventionally known biasing means such as a coil spring without requiring the supply of electricity or air pressure. Incidentally, the first supply valve 91 used is one that maintains the airtight seal of the first chamber 56 when normally closed.

[0067] Furthermore, as will be described in detail later, in the event of an abnormality, one of the second supply valve 92 and the third supply valve 93 in this embodiment automatically closes to prevent the air in one of the second chambers 57 and the third chamber 58 from being discharged to the outside, while the other opens to discharge the air in the other of the second chamber 57 and the third chamber 58 to the outside, i.e., to the atmosphere. In other words, in the event of an abnormality, the pressure in one of the second chambers 57 and the third chamber 58 is maintained, while the other is opened to the atmosphere and becomes atmospheric pressure. In this embodiment, in the event of an abnormality, the second supply valve 92 is closed to maintain the pressure in the second chamber 57, and the third supply valve 93 is opened to open the third chamber 58 to the atmosphere. The second supply valve 92 is a normally closed valve device that automatically closes in the event of an abnormality using a conventionally known biasing means such as a coil spring without requiring the supply of electricity or air pressure. The second supply valve 92 is one that maintains the sealing of the second chamber 57 when normally closed. Furthermore, the third supply valve 93 uses a normally open valve device that automatically opens in the event of an abnormality.

[0068] Furthermore, the cylinder body 51 is provided with a first connection port 101, a second connection port 102, and a third connection port 103.

[0069] The first connection port 101 is provided to connect the first chamber 56 to the outside. The second connection port 102 is provided to connect the second chamber 57 to the outside. The third connection port 103 is provided to connect the third chamber 58 to the outside. A connecting part 105 is fixed to each of the first connection port 101, second connection port 102, and third connection port 103. In addition, the second connection port 102 and the third connection port 103 are provided in positions that are not blocked by the piston 60 when the piston 60 moves, similar to the second flow port 82 and the third flow port 83.

[0070] The first chamber 56 and the second chamber 57 or the third chamber 58 are connected by piping 106. In this embodiment, the first chamber 56 and the second chamber 57 are connected by piping 106. A switching valve 107, which is the switching means of this embodiment, is provided in the middle of piping 106. The switching valve 107 switches between communication and non-communication between the first chamber 56 and the second chamber 57, or between communication and non-communication between the first chamber 56 and the third chamber 58. In this embodiment, since piping 106 connects the first chamber 56 and the second chamber 57, the switching valve 107 switches between communication and non-communication between the first chamber 56 and the second chamber 57. Such a switching valve 107 consists of a solenoid valve or an electric valve. In addition, under normal conditions, the switching valve 107 of this embodiment maintains a closed state, that is, a non-communication state between the first chamber 56 and the second chamber 57, under the control of the control unit 100. Furthermore, the switching valve 107 is a normally open valve device and automatically opens in the event of an abnormality to connect the first chamber 56 and the second chamber 57. In addition, in this embodiment, the connection portion 105 of the third connection port 103 is sealed by the cover member 108, so that the third chamber 58 is not discharged to the outside from the third connection port 103.

[0071] <Valve head> The valve head 4 is a component in which the first supply valve 91, second supply valve 92, third supply valve 93, switching valve 107, and control unit 100 described above are housed in a case (not shown). The valve head 4 may also include sensors (not shown) for detecting the open and closed states of the valve body 2, a display device for displaying the operating status of the valve body 2, and electrical components for controlling the operation and display of the working status of the first to third supply valves 91 to 93 and the switching valve 107.

[0072] <Normal valve closing> In a valve device 1 having such an air motor 3, in order to close the valve body 2 under normal conditions, the pressure adjustment means, under the control of the control unit 100, increases the pressure in the second chamber 57 to be greater than the pressure in the third chamber 58, thereby moving the piston 60 toward the second cap 52B, as shown in Figure 2, and bringing the valve body 30 into contact with the valve seat 15 to close the valve.

[0073] To make the pressure in the second chamber 57 greater than the pressure in the third chamber 58, for example, this can be done by supplying gas to the second chamber 57 from the pump 87B while the third chamber 58 is open to the atmosphere. There are various ways to open the third chamber 58 to the atmosphere. For example, this can be done by opening the third supply valve 93 and stopping the pump 87C. This is applicable when the configuration is such that when the pump 87C stops, the connection to the pump 87C is opened to the atmosphere. Alternatively, an atmospheric release valve can be installed between the pump 87C and the third supply valve 93 or in the piping 86C, and this atmospheric release valve can be opened. The pump 87C is stopped when the atmospheric release valve is opened, but it may also be kept running. Incidentally, when opening the third chamber 58 to the atmosphere using an atmospheric release valve, the atmospheric release valve should be a normally open valve device that opens automatically in the event of an abnormality. Furthermore, a three-way valve with one end open to the atmosphere may be used as the third supply valve 93. When using such a three-way valve, the configuration should be such that one side of the valve is closed under normal conditions, and the other side automatically opens in the event of an abnormality.

[0074] Another method involves, for example, driving the pump 87B connected to the second chamber 57 to supply compressed air to the second chamber 57, thereby creating a positive pressure (also called positive pressure) in the second chamber 57 that is higher than atmospheric pressure, while simultaneously driving the pump 87C connected to the third chamber 58 in the opposite direction to create a negative pressure in the third chamber 58 that is lower than atmospheric pressure.

[0075] Another method is to make both the second chamber 57 and the third chamber 58 positive pressure above atmospheric pressure, while making the pressure in the second chamber 57 greater than the pressure in the third chamber 58. As a method to make both the second chamber 57 and the third chamber 58 positive pressure while making the pressure in the second chamber 57 greater than that in the third chamber 58, for example, the output of the pump 87B that supplies compressed air to the second chamber 57 is greater than the output of the pump 87C that supplies compressed air to the third chamber 58, or, if the second supply valve 92 and the third supply valve 93 have a function to adjust their opening degree using pumps 87B and 87C with the same output, the opening degree of these valves is adjusted to adjust the pressure of the gas supplied to the second chamber 57 and the third chamber 58. If the second supply valve 92 and the third supply valve 93 do not have a function to adjust the pressure, a separate pressure adjustment valve capable of adjusting the pressure may be provided and the opening degree of the pressure adjustment valve may be adjusted.

[0076] <Normal valve opening> To open the valve body 2, the pressure adjustment means, under the control of the control unit 100, increases the pressure in the third chamber 58 to be greater than the pressure in the second chamber 57, thereby moving the piston 60 toward the first cap 52A, as shown in Figure 3, and separating the valve body 30 from the valve seat 15 to open the valve.

[0077] To make the pressure in the third chamber 58 greater than the pressure in the second chamber 57, one method is to use the reverse configuration described above for when the valve is closed, that is, to supply gas to the third chamber 58 from the pump 87C while the second chamber 57 is open to the atmosphere. Another method is to drive the pump 87C connected to the third chamber 58 to supply compressed air to the third chamber 58, making the pressure in the third chamber 58 positive above atmospheric pressure, while simultaneously driving the pump 87B connected to the second chamber 57 in the opposite direction to make the pressure in the second chamber 57 negative above atmospheric pressure. Yet another method is to make the pressure in the third chamber 58 greater than the pressure in the second chamber 57 while making the pressure in both the second chamber 57 and the third chamber 58 positive above atmospheric pressure. To open the second chamber 57 to the atmosphere, various means can be used, similar to opening the third chamber 58 to the atmosphere as described above. For example, this can be done by opening the second supply valve 92 and stopping the pump 87B. This can be applied when the configuration is such that when pump 87B stops, the connection to pump 87B is opened to the atmosphere. Alternatively, an atmospheric release valve may be installed between pump 87B and the second supply valve 92 or in the piping 86B, and this can be done by opening the atmospheric release valve. When the atmospheric release valve is opened, pump 87B is stopped, but it may also be kept running. Incidentally, when opening the second chamber 57 to the atmosphere using an atmospheric release valve, a normally open valve device that automatically opens in the event of a malfunction should be used for the atmospheric release valve. Furthermore, a three-way valve with one end open to the atmosphere may be used as the second supply valve 92. When using such a three-way valve, one end of the three-way valve should be closed under normal conditions, and the other end should be automatically opened in the event of a malfunction.

[0078] As described above, the control of the air motor 3 is performed based on commands from the control unit 100 located in the valve head 4.

[0079] On the other hand, under normal conditions, the pressure adjustment means, under the control of the control unit 100, adjusts the pressure in the first chamber 56 in preparation for emergencies. In this embodiment, under the control of the control unit 100, the pressure adjustment means keeps the pressure in the first chamber 56 higher than the pressures in the second chamber 57 and the third chamber 58. To make the pressure in the first chamber 56 higher than the pressures in the second chamber 57 and the third chamber 58, for example, the output of the pump 87A that supplies gas to the first chamber 56 is made higher than that of the pumps 87B and 87C that supply gas to the second chamber 57 and the third chamber 58, or, if the first supply valves 91 to the third supply valves 93 have a function to adjust their opening degree using pumps 87A to 87C with the same output, the opening degree of these valves is adjusted. If the first supply valves 91 to the third supply valves 93 do not have a function to adjust the pressure, a separate pressure adjustment valve capable of adjusting the pressure may be provided and the opening degree of the pressure adjustment valve may be adjusted. Furthermore, after supplying gas to the first chamber 56, the first supply valve 91 communicating with the first chamber 56 is closed. This maintains the pressure in the first chamber 56 at a level greater than the pressures in the second chamber 57 and the third chamber 58. Of course, since the first supply valve 91 is a normally closed valve device that closes when the power supply is cut off, the first supply valve 91 communicating with the first chamber 56 may be kept open under normal circumstances, so that the pump 87A can continuously supply gas to the first chamber 56.

[0080] As described above, under normal circumstances, when the valve body 2 is opened and closed by the gas supplied from pumps 87B and 87C, the switching valve 107 is closed, preventing the first chamber 56 and the second chamber 57 from communicating. In other words, the switching valve 107 does not connect the first connection port 101 and the second connection port 102. This means that the first chamber 56 is isolated from the second chamber 57, and a higher pressure is maintained in the first chamber 56 than in the second chamber 57.

[0081] <Reverse Acting System> Figure 4 is a cross-sectional view of the valve body 2 and air motor 3 illustrating the valve closing operation of the valve device 1 according to this embodiment.

[0082] In the event of a power outage or a malfunction of pumps 87B or 87C that interrupts the supply of compressed air to the second chamber 57 and the third chamber 58, the valve body 2 is closed. This operation is called the reverse-acting method. In other words, in the reverse-acting method, the pressure of the first chamber 56 is used to move the piston 60 and close the valve body 2 without adjusting the pressure in the second chamber 57 and the third chamber 58 using the pressure adjustment means.

[0083] In the reverse-acting method, the switching valve 107 connects the first chamber 56 and the second chamber 57 from a state where they are not connected. That is, it connects the first connection port 101 and the second connection port 102. Since the switching valve 107 in this embodiment is a normally open valve device that opens when the power is cut off, in the event of an abnormality, the switching valve 107 can connect the first chamber 56 and the second chamber 57 without being controlled by the control unit 100. At this time, the first chamber 56 and the third chamber 58 are not connected.

[0084] Furthermore, the second supply valve 92 in this embodiment is a normally closed valve device that automatically closes in the event of an abnormality, so in the event of an abnormality, the second supply valve 92 closes and seals the second chamber 57. Also, the third supply valve 93 in this embodiment is a normally open valve device that automatically opens in the event of an abnormality, so in the event of an abnormality, the third supply valve 93 opens and opens the third chamber 58 to the atmosphere.

[0085] As a result, compressed air in the first chamber 56 is supplied to the second chamber 57 via the first connection port 101 and the second connection port 102. At this time, since the second chamber 57 is sealed, compressed air is supplied from the first chamber 56 to the second chamber 57 until the pressure in the first chamber 56 and the second chamber 57 are equal. If the valve body 2 is open, the pressure in the second chamber 57 becomes greater than the pressure in the third chamber 58 (atmospheric pressure in this embodiment), causing the piston 60 to move toward the second cap 52B, as shown in Figure 4, and the valve body 30 to contact the valve seat 15 and close the valve. In other words, when the supply of compressed air from pumps 87A to 87C stops, the valve body 2 can be closed by supplying compressed air to the second chamber 57 from the first chamber 56, which has been holding compressed air at a higher pressure beforehand.

[0086] The pressure applied by the air motor 3 to the valve body 30 is called the supply pressure. This supply pressure is required to be set higher than the allowable pressure. The allowable pressure is the pressure sufficient to maintain the state in which the valve body 30 is in contact with the valve seat 15 and the inlet 13 is closed. In other words, if the supply pressure exceeds the allowable pressure, the valve body 30 will not open due to the pressure of the fluid in the piping.

[0087] Assuming that the switching valve 107 is not activated in the event of an abnormality, the supply of compressed air to the second chamber 57 will cease. Therefore, even if the second supply valve 92 is closed, the pressure inside the second chamber 57 will decrease, and there is a risk that the supply pressure will fall below the allowable pressure.

[0088] However, in this invention, when an abnormality occurs, the switching valve 107 is activated, causing the first chamber 56 and the second chamber 57 to communicate. Since the first chamber 56 is filled with air at a higher pressure than the second chamber 57, the pressure between the communicating first chamber 56 and the second chamber 57 is maintained at or above the pressure of the third chamber 58. Therefore, when an abnormality occurs, the valve body 30 can be brought into contact with the valve seat 15 with a supply pressure equal to or greater than the allowable pressure, thereby closing the inlet 13.

[0089] The pressure to be set in the first chamber 56 under normal conditions is set so that, when the first chamber 56 and the second chamber 57 are in communication under abnormal conditions, the differential pressure between the second chamber 57 and the third chamber 58 exceeds the allowable pressure. In other words, it is set so that the valve is closed due to this differential pressure. An example of the setting is shown in Table 1. Atmospheric pressure is used as the reference (0.0 MPa), and the allowable pressure is 0.5 MPa. First, under normal conditions, the pressure in the second chamber 57 is 0.5 MPa and the pressure in the third chamber 58 is 0.0 MPa, and the valve is closed due to this differential pressure. When the valve switches to a communication state under abnormal conditions, the pressures in the first chamber 56 and the second chamber 57 become the same, but in the example in Table 1, it is 1.25 MPa. Even under abnormal conditions, the third chamber 58 is open to the atmosphere, so the pressure in the first chamber 56 under normal conditions is set so that the differential pressure between 1.25 MPa and 0.0 MPa exceeds the allowable pressure of 0.5 MPa. In this example, the pressure in the first chamber 56 under normal conditions is 2.0 MPa.

[0090] [Table 1]

[0091] In the example in Table 1, the valve was closed under normal conditions, but even if the valve is open under normal conditions, the pressure of the first chamber 56 should be set in the same manner. Also, although not specifically illustrated, even if the third chamber 58 is not opened to the atmosphere under abnormal conditions and is sealed at a pressure greater than atmospheric pressure, the pressure of the first chamber 56 under normal conditions should be set in the same manner. For example, if the third chamber 58 is to be sealed under abnormal conditions, a normally closed valve device should be used as the third supply valve 93.

[0092] In normal operation, the pressure in the first chamber 56 is set higher than the pressure in the second chamber 57, which is connected to it. However, if the pressure after connection satisfies the allowable pressure, the two chambers may be the same. Also, the volume of the second chamber 57 is variable due to the movement of the piston 60. Therefore, the pressure in the second chamber 57 described above is the pressure when the piston 60 is at its lowest position and the volume of the second chamber 57 is at its maximum in this reverse-acting embodiment. The pressure set in the first chamber 56 in normal operation is determined by considering the volume of the first chamber 56, the volume of the second chamber 57, and the allowable pressure.

[0093] Furthermore, in this embodiment, since the valve closing operation can be performed without using a biasing means such as a coil spring, it becomes unnecessary to implement a biasing means such as a coil spring having a considerable mass and elasticity in order to implement the required biasing force, and a container structure having a volume that can house this biasing means, thus enabling miniaturization and weight reduction.

[0094] (Embodiment 2) Figure 5 is a diagram showing the schematic configuration of a valve device 1 according to Embodiment 2 of the present invention. Figure 6 is a cross-sectional view of the valve body 2 and air motor 3 illustrating the valve opening operation of the valve device 1 according to this embodiment. Note that the same reference numerals are used for components similar to those in Embodiment 1 described above, and redundant explanations are omitted.

[0095] As shown in Figures 5 and 6, in the valve device 1 of this embodiment, the first chamber 56 and the third chamber 58 are connected by piping 106. A switching valve 107, which is the switching means of this embodiment, is provided in the middle of the piping 106. The switching valve 107 switches between communication and non-communication between the first chamber 56 and the third chamber 58. The switching valve 107 consists of a solenoid valve or an electric valve controlled by the control unit 100, similar to Embodiment 1. In addition, in this embodiment, the switching valve 107 is kept closed under the control of the control unit 100 during normal operation, that is, the first chamber 56 and the third chamber 58 are not in communication. Furthermore, the switching valve 107 is a normally open valve device, and in the event of an abnormality, it automatically opens to connect the first chamber 56 and the third chamber 58. In addition, in this embodiment, the connection portion 105 of the second connection port 102 is sealed by a cover member 108, so that the second chamber 57 is not discharged to the outside from the second connection port 102.

[0096] Furthermore, the first supply valve 91 is a normally closed valve device that automatically closes in the event of an abnormality, similar to Embodiment 1 described above. The second supply valve 92 is a normally open valve device that automatically opens in the event of an abnormality. In other words, in the event of an abnormality, the second supply valve 92 automatically opens, opening the second chamber 57 to the atmosphere. The third supply valve 93 is a normally open valve device that automatically closes in the event of an abnormality. Incidentally, the third supply valve 93 is one that maintains the airtight seal of the third chamber 58 when normally closed. Therefore, in the event of an abnormality, the third supply valve 93 automatically closes, sealing the third chamber 58.

[0097] <Normal Operation Method> In the event of a power outage or an abnormality such as a pump failure or piping failure that interrupts the supply of compressed air to the second chamber 57 and the third chamber 58, the valve body 2 is opened. This operation is called the normal operating mode. In other words, in the normal operating mode, the pressure in the first chamber 56 is used to move the piston 60 and open the valve body 2 without adjusting the pressure in the second chamber 57 and the third chamber 58 using the pressure adjustment means.

[0098] In the normal operating mode, the switching valve 107 connects the first chamber 56 and the third chamber 58 from a state where they are not connected. That is, it connects the first connection port 101 and the third connection port 103. Since the switching valve 107 in this embodiment is a normally open valve device that opens when the power is cut off, in the event of an abnormality, the switching valve 107 can connect the first chamber 56 and the third chamber 58 without being controlled by the control unit 100. At this time, the first chamber 56 and the second chamber 57 are not connected.

[0099] Furthermore, the second supply valve 92 in this embodiment is a normally open valve device that automatically opens in the event of an abnormality, so in the event of an abnormality, the second supply valve 92 opens and opens the second chamber 57 to the atmosphere. Also, the third supply valve 93 in this embodiment is a normally closed valve device that automatically closes in the event of an abnormality, so in the event of an abnormality, the third supply valve 93 closes and seals the third chamber 58.

[0100] As a result, compressed air in the first chamber 56 is supplied to the third chamber 58 via the first connection port 101 and the third connection port 103. At this time, since the third chamber 58 is sealed, compressed air is supplied from the first chamber 56 to the third chamber 58 until the pressures in the first chamber 56 and the third chamber 58 become equal. If the valve body 2 is closed, the pressure in the third chamber 58 becomes greater than the pressure in the second chamber 57, causing the piston 60 to move toward the first cap 52A, as shown in Figure 6, and the valve body 30 to move away from the valve seat 15, thereby opening the valve. In other words, when the supply of compressed air from pumps 87A to 87C stops, the valve can be opened by supplying compressed air to the third chamber 58 from the first chamber 56, which has been holding compressed air at a higher pressure beforehand. Furthermore, if the valve body 2 is open, the pressure in the third chamber 58 will be greater than the pressure in the second chamber 57 (atmospheric pressure in this embodiment), thereby maintaining the open state of the valve body 2 and preventing it from closing unexpectedly due to shock or other reasons. In other words, assuming that the switching valve 107 is not activated in the event of an abnormality, the supply of compressed air to the third chamber 58 will cease, so even if the third supply valve 93 is closed, the pressure in the third chamber 58 will drop, and there is a risk that the valve body 2 will close.

[0101] However, in this invention, when an abnormality occurs, the switching valve 107 is activated, causing the first chamber 56 and the third chamber 58 to communicate. Since the first chamber 56 is filled with air at a higher pressure than the third chamber 58, the pressure in the communicating first chamber 56 and the third chamber 58 is maintained at or above the pressure in the second chamber 57. Therefore, when an abnormality occurs, the valve body 2 can be opened, preventing it from closing at an unexpected time due to impact or other reasons, and preventing a decrease in the flow rate passing from the inlet 13 to the outlet 14 due to a decrease in the height position of the valve body 30.

[0102] Furthermore, the pressure in the first chamber 56 is set to exceed the allowable pressure when the valve is open, resulting in the maximum volume of the third chamber 58, and the first chamber 56 and the third chamber 58 are in communication and have the same pressure.

[0103] The pressure to be set in the first chamber 56 under normal conditions is set so that when the first chamber 56 and the third chamber 58 are connected under abnormal conditions, the valve opens due to the pressure difference between the second chamber 57 and the third chamber 58. An example of the setting is shown in Table 2. Atmospheric pressure is used as the reference (0.0 MPa). First, under normal conditions, the pressure in the second chamber 57 is 0.5 MPa and the pressure in the third chamber 58 is 0.0 MPa, and this pressure difference keeps the valve closed. When the valve switches to a connected state under abnormal conditions, the pressures in the first chamber 56 and the third chamber 58 become the same, but in the example in Table 2, it becomes 1.0 MPa. Under abnormal conditions, the second chamber 57 is opened to the atmosphere, so a pressure difference between 1.0 MPa and 0.0 MPa is created, causing the valve to open. In this way, the pressure in the first chamber 56 under normal conditions is set so that the valve opens due to this pressure difference under abnormal conditions. In this example, the pressure in the first chamber 56 under normal conditions is 2.0 MPa.

[0104] [Table 2]

[0105] In the example in Table 2, the valve was closed under normal conditions, but even if the valve is open under normal conditions, the pressure of the first chamber 56 should be set in the same manner. Also, although not specifically illustrated, even if the second chamber 57 is not opened to the atmosphere under abnormal conditions and is sealed at a pressure greater than atmospheric pressure, the pressure of the first chamber 56 under normal conditions should be set in the same manner. For example, if the second chamber 57 is sealed under abnormal conditions, a normally closed valve device should be used as the second supply valve 92.

[0106] In normal operation, the pressure in the first chamber 56 is set higher than the pressure in the third chamber 58, which is connected to it. However, if the pressure after connection satisfies the allowable pressure, the two chambers may be the same. Also, the volume of the third chamber 58 is variable due to the movement of the piston 60. Therefore, the pressure in the third chamber 58 described above is the pressure when the piston 60 is raised to its highest position and the volume of the third chamber 58 is at its maximum in this embodiment of normal operation. The pressure set in the first chamber 56 in normal operation is determined by considering the volume of the first chamber 56, the volume of the third chamber 58, and the allowable pressure.

[0107] Furthermore, in this embodiment, since the valve can be opened without using a biasing means such as a coil spring, it becomes unnecessary to implement a biasing means such as a coil spring having a considerable mass and elasticity to implement the required biasing force, and a container structure having a volume to house this biasing means, thus enabling miniaturization and weight reduction.

[0108] (Other embodiments) Although various embodiments of the present invention have been described above, the basic configuration of the present invention is not limited to those described above.

[0109] For example, in embodiments 1 and 2 described above, pumps 87A to 87C are provided to supply compressed air to each of the first chambers 56 to the third chamber 58, but the invention is not limited to this, and compressed air may be supplied to the first chambers 56 to the third chamber 58 from a single pump. In this case, pressure adjustment can be performed by providing pressure adjustment valves in each of the pipes 86A to 86C connected to the first chambers 56 to the third chamber 58, and adjusting the pressure adjustment valves with the control unit 100 to adjust the pressure in the first chamber 56, the second chamber 57, and the third chamber 58. Of course, the pressure adjustment valves may also be combined into the first supply valves 91 to the third supply valves 93.

[0110] Furthermore, in the above-described embodiment 1, the pressure in the first chamber 56 was made greater than the pressures in the second chamber 57 and the third chamber 58 in order to operate in reverse mode in the event of an abnormality. However, the invention is not limited to this, and even if the pressure in the first chamber 56 is positive and less than or equal to the pressures in the second chamber 57 and the third chamber 58, if the pressure in the second chamber 57, which is in communication with the first chamber 56 in the event of an abnormality, is sufficiently greater than the pressure in the third chamber 58, the invention can be operated in reverse mode. Similarly, although the pressure in the first chamber 56 was made greater than the pressures in the second chamber 57 and the third chamber 58 in order to operate in forward mode in the event of an abnormality, the invention is not limited to this, and even if the pressure in the first chamber 56 is positive and less than or equal to the pressures in the second chamber 57 and the third chamber 58, if the pressure in the third chamber 58, which is in communication with the first chamber 56 in the event of an abnormality, is sufficiently greater than the pressure in the second chamber 57, the invention can be operated in forward mode. In this manner, when the pressure in the first chamber 56 is lower than the pressures in the second chamber 57 and the third chamber 58, the normal operation of the second supply valve 92 and the third supply valve 93, the operation of the second supply valve 92 and the third supply valve 93 in the event of an abnormality, and the connection destination of the switching valve 107 can be appropriately set so that they operate in reverse and forward operation modes in the event of an abnormality.

[0111] Furthermore, in embodiments 1 and 2 described above, pumps 87A to 87C, which are compressors that supply compressed air as a gas supply source, were exemplified. However, the gas supply source is not limited to one that supplies gas, but may also be one that sucks gas. In other words, at least one of pumps 87A to 87C may be a vacuum pump. For example, the opening and closing of the valves under normal conditions may be performed by creating a negative pressure lower than atmospheric pressure in the second chamber 57 and a negative pressure lower than atmospheric pressure in the third chamber 58, and using the pressure difference between the two negative pressures. Of course, either the second chamber 57 or the third chamber 58 may be under positive pressure and the other under negative pressure. Alternatively, one of the second chamber 57 or the third chamber 58 may be under negative pressure and the other open to the atmosphere.

[0112] Furthermore, when operating in reverse-acting or forward-acting mode, at least one of the first chamber 56, second chamber 57, and third chamber 58 may be set to negative pressure. For example, if one of the first chamber 56, second chamber 57, and third chamber 58 is set to negative pressure, the other two may be set to positive pressure, negative pressure, or atmospheric pressure in an appropriate combination. In other words, the combination of positive pressure, negative pressure, and atmospheric pressure for each of the first chamber 56, second chamber 57, and third chamber 58 can be appropriately configured so that the switching valve 107 operates in reverse-acting or forward-acting mode when the first chamber 56 and second chamber 57 are connected, or when the first chamber 56 and third chamber 58 are connected. In addition, the normal control of the second supply valve 92 and third supply valve 93, the abnormal operation of the second supply valve 92 and third supply valve 93, and the connection destination of the switching valve 107 can be appropriately set according to the combination.

[0113] Furthermore, for example, pressure detection means may be provided on the valve head 4 to detect the pressure of the gas supplied to the second chamber 57 and the third chamber 58, respectively. Specifically, for example, pressure detection means may be provided between the pump 87B of piping 86B and the second supply valve 92, and between the pump 87C of piping 86C and the third supply valve 93, respectively, to detect the pressure of the gas supplied from pumps 87B and 87C to the second chamber 57 and the third chamber 58, respectively. The control unit 100 may then determine that an abnormality has occurred when the pressure of at least one of the gases supplied to the second chamber 57 and the third chamber 58, as detected by the pressure detection means, falls below a preset threshold, and switch the switching valve 107 from the normal closed state to the open state to operate in reverse-acting or forward-acting mode. In other words, if the control unit 100 is unable to supply gas to the second chamber 57 and the third chamber 58 at the pressure necessary to drive the air motor 3 due to a malfunction of the pumps 87B and 87C or damage to the piping 86B and 86C, the switching valve 107 switches from the normal closed state to the open state. This ensures that even when the power supply is not cut off, the valve body 2 does not enter an unintended state due to a malfunction of the pumps 87B and 87C or the piping 86B and 86C, and can be set to the desired closed state (reverse acting mode) or open state (forward acting mode). Incidentally, if the control unit 100 determines that there is an abnormality based on the pressure detected by the pressure detection means, it should simultaneously control the second supply valve 92 and the third supply valve 93 as appropriate so that they can operate in reverse acting mode or forward acting mode.

[0114] Furthermore, in Embodiment 1 described above, a configuration was shown in which a piping 106 equipped with a switching valve 107 is connected to the first chamber 56 and the second chamber 57 in order to perform a valve closing operation in the event of an abnormality, and in Embodiment 2, a configuration was shown in which a piping 106 equipped with a switching valve 107 is connected to the first chamber 56 and the third chamber 58 in order to perform a valve opening operation in the event of an abnormality. However, the following methods can be used to switch between these forward-acting and reverse-acting modes. For example, the piping 106 connecting the switching valve 107 to the second chamber 57 and the third chamber 58 may be connected with a flexible tube, and the forward-acting and reverse-acting modes can be switched by switching the connection destination of the tube between the second chamber 57 and the third chamber 58. In other words, in the valve device 1 of Embodiments 1 and 2 described above, the forward-acting and reverse-acting modes can be easily switched by a simple method of changing the connection destination of the tube without replacing the air motor 3. In contrast, when using an air motor with a coil spring, it is necessary to switch between the forward operating mode and the reverse operating mode by replacing the air motor for opening the valve and the air motor for closing the valve, which cannot be easily switched.

[0115] Furthermore, in embodiments 1 and 2 described above, the first chamber 56 is provided within the cylinder body 51, separated from the cylinder chamber 54 by a partition wall 53. However, the invention is not limited to this, and the first chamber 56 may be provided in a separate component from the cylinder body 51, isolated from the cylinder chamber 54. However, by providing the first chamber 56 inside the cylinder body 51, as in embodiments 1 and 2 described above, the number of parts of the air motor 3 can be reduced and miniaturization can be achieved.

[0116] Furthermore, although the valve body 30 and the diaphragm 40 are separate components in the embodiments 1 and 2 described above, the invention is not limited to this, and a so-called integrated diaphragm, in which the valve body 30 and the diaphragm 40 are formed from an elastomer or the like, may also be used.

[0117] Furthermore, while embodiments 1 and 2 described above illustrate a configuration in which an air motor 3 is used in the valve device 1, the air motor of the present invention can also be used in devices other than the valve device 1. In other words, in the event of an abnormality such as a power outage or when gas cannot be supplied at a predetermined pressure due to a pump failure or damage to the piping, the air motor can be controlled to perform a desired operation, namely the position of the cylinder rod. [Explanation of Symbols]

[0118] 1... Valve device, 2... Valve body, 3... Air motor, 4... Valve head, 5... Joint rod, 5a... Screw hole, 10... Flow path member, 11... Flow path, 12... Valve chamber, 12a... Valve port, 13... Inlet, 14... Outlet, 15... Valve seat, 16... Opening, 17... Projection, 20... Fixing member, 21... Second insertion hole, 22... Back plate housing, 23... Clamp, 24... Connection space 25...Fixing part, 26...Fixing opening, 27...Fourth insertion hole, 28...Fixing screw, 30...Valve body, 31...Valve body part, 32...Valve shaft part, 33...Contact part, 34...Mounting part, 35...Stepped part, 40...Diaphragm, 41...First insertion hole, 42...Back plate, 43...Third insertion hole, 43a...Third insertion hole, 43b...Third insertion hole, 50...Cylinder, 51...Cylinder body, 52...Cylinder 52a…Step, 52A…First cap, 52b…Screw hole, 52B…Second cap, 52c…First projection, 53…Wall, 54…Cylinder chamber, 55…Fifth insertion hole, 56…First chamber, 57…Second chamber, 58…Third chamber, 59…Sixth insertion hole, 60…Piston, 61…Fixing hole, 62…Retaining part, 63…O-ring, 64…Second projection, 70…Cylinder rod, 81…First Flow port, 82...Second flow port, 83...Third flow port, 85...Connection part, 86A~86C...Piping, 87A~87C...Pump, 91...First supply valve, 92...Second supply valve, 93...Third supply valve, 100...Control unit, 101...First connection port, 102...Second connection port, 103...Third connection port, 105...Connection part, 106...Piping, 107...Switching valve, 108...Cover member

Claims

1. The valve device comprises a cylinder rod attached to the valve body, a cylinder body having a cylinder chamber, a piston connected to the cylinder rod and provided to move the cylinder chamber in the axial direction of the cylinder rod, a first chamber isolated from the cylinder chamber, a pressure regulating means for regulating the pressure of the gas supplied from a gas supply source, and a control unit for controlling the operation of the pressure regulating means. The cylinder chamber comprises a second chamber and a third chamber separated by the piston, An air motor in which the piston is moved by adjusting the pressure of the gas inside the second and third chambers by the pressure adjustment means under the control of the control unit, Under the control of the control unit, the pressure adjustment means adjusts the pressure in the first chamber. The system includes a switching means for switching between communication and non-communication between the first room and the second room, or between communication and non-communication between the first room and the third room, under the control of the control unit. An air motor characterized by the following features.

2. With the switching means in a state where the first chamber and the second chamber are not in communication, and the first chamber and the third chamber are not in communication, the pressure adjusting means adjusts the pressure in the second chamber and the third chamber, thereby moving the piston. The switching means connects the first chamber and the second chamber, supplying gas from the first chamber to the second chamber, or supplying gas from the second chamber to the first chamber, thereby moving the piston without adjusting the pressure in the second and third chambers by the pressure adjusting means. The air motor according to feature 1.

3. With the switching means in a state where the first chamber and the second chamber are not in communication, and the first chamber and the third chamber are not in communication, the pressure adjusting means adjusts the pressure in the second chamber and the third chamber, thereby moving the piston. The switching means connects the first chamber and the third chamber, supplying gas from the first chamber to the third chamber, or supplying gas from the third chamber to the first chamber, thereby moving the piston without adjusting the pressure in the second and third chambers by the pressure adjusting means. The air motor according to feature 1.

4. The switching means includes a switching valve that opens when power is not supplied. The air motor according to feature 1.

5. The pressure adjusting means is The gas supply source for pressurizing or aspirating gas, A first supply valve connected between the gas supply source and the first chamber, Includes, The first supply valve closes when no power is supplied. The air motor according to feature 1.

6. The device is equipped with pressure detection means for detecting the pressure of the gas supplied to the second chamber and the third chamber, respectively. The control unit switches the switching means based on the pressure of at least one of the gases supplied to the second chamber and the third chamber, as detected by the pressure detection means. The air motor according to feature 1.

7. An air motor according to any one of claims 1 to 6, A valve body comprising a valve element attached to the cylinder rod of the air motor and a flow path that is opened and closed by the valve element, Equipped with, A valve device characterized by the following features.

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