JP4041132B2 - Air cylinder drive - Google Patents

Description

  The present invention relates to an air cylinder driving apparatus suitably used for opening and closing, for example, a butterfly valve, various control valves, a damper switch, and the like provided in the middle of fluid piping by an air cylinder.

  In general, an air cylinder configured to open and close, for example, a large valve or a damper by remote operation by supplying and discharging pressurized air made of compressed air to and from an air cylinder and expanding and contracting the rod of the air cylinder. Drive devices are known.

  This type of prior art air cylinder drive device expands and contracts the rod by supplying pressure air such as an air pump (air compressor) for supplying pressurized air, an air tank, etc., and supplying and discharging pressurized air from the pressure source. An air cylinder and a positioner provided between the air cylinder and a pressure source and variably controlling the amount of air supplied to and discharged from the air cylinder according to a command signal are configured (for example, see Patent Document 1).

  The positioner in this case has a function of performing feedback control for extending and retracting the air cylinder by remote operation. That is, when a command signal having an arbitrary value is output from an external command device, the positioner is controlled by the pressure source so that the rod of the air cylinder is expanded and contracted in a proportionally linear characteristic according to the value of the command signal. The amount of air supplied to and discharged from the air cylinder is variably controlled.

JP 2003-239910 A

  By the way, in the above-described prior art air cylinder driving device, for example, in the middle of assembling the device, in contrast to the so-called automatic mode control in which the air cylinder is automatically operated via the positioner by the pressurized air from the pressure source. When performing a maintenance check or the like, there is a case where control in a so-called manual mode in which the air cylinder is operated manually is required.

  However, in order to switch between the manual mode control and the automatic mode control, for example, a clutch mechanism having a complicated structure is generally provided on the tube (main body) side of the air cylinder, for example. This increases the overall size of the air cylinder, which makes it difficult to secure the installation space for the apparatus, and increases the production cost and assembly cost.

  Therefore, the present inventors generate the necessary air pressure (auxiliary air) by manual operation using, for example, a small hand pump, and supply and discharge this auxiliary air to and from the air cylinder to drive the rod to extend and contract in a so-called manual mode. Considered to do.

  However, in order to realize the drive control of the air cylinder in such a manual mode, an air pressure circuit for an automatic mode that controls the air cylinder in an automatic mode via the positioner or the like, and an air pressure for the automatic mode are provided. An air pressure circuit for manual mode connected to the air cylinder in parallel with the pressure circuit is required.

  In order to selectively switch between these two air pressure circuits, a circuit shut-off valve for selectively connecting and shutting off each air pressure circuit to the air cylinder is provided for each air pressure circuit. Need to be provided separately. Moreover, when opening and closing the circuit shut-off valve on one air pressure circuit side, it is necessary to simultaneously open and close the circuit shut-off valve on the other air pressure circuit side. There is an unsolved problem that the opening / closing operation of the circuit shut-off valve becomes complicated.

  In order to extend or stop the air cylinder by the air pressure circuit for the manual mode, a manual operation valve for supplying / discharging and stopping the auxiliary air generated by the manual operation to the air cylinder is provided in the manual mode. Must be provided in the middle of the air pressure circuit.

  However, as long as a commercially available manual operation valve is used, it is difficult to ensure sufficient airtightness. For example, when air leakage occurs from the manual operation valve, the expansion / contraction position of the air cylinder changes, and the device This will cause the stability and reliability of the product to deteriorate.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to selectively control driving of an air cylinder in an automatic mode and a manual mode. An object of the present invention is to provide an air cylinder driving device which can be easily performed and can improve operability.

  Another object of the present invention is to suppress the occurrence of air leakage from the mode switching valve even when a mode switching valve is provided in the middle of the air pressure circuit instead of a commercially available manual operation valve, for example. An object of the present invention is to provide an air cylinder driving device capable of ensuring the reliability and stability of the device.

  In order to solve the above-described problems, the present invention provides a pressure source that supplies pressurized air, an air cylinder in which a rod is expanded and contracted by the pressurized air from the pressure source, and a space between the air cylinder and the pressure source. And is applied to an air cylinder driving device comprising a positioner that variably controls the amount of air supplied to and discharged from the air cylinder according to a command signal.

The feature of the configuration adopted by the invention of claim 1 is that between the air cylinder and the positioner, when the pilot pressure supplied from the outside is higher than the set pressure, the space between the positioner and the air cylinder is A circuit shut-off valve is provided for shutting between the two when the pilot pressure is reduced to an atmospheric pressure level, and the circuit shut-off valve and the air cylinder are branched from an air pipe connecting the two. through a branch pipe provided a mode switching valve, the mode switching valve, and an automatic mode for operating the air cylinder by the pressurized air from the pressure source discharge sheet with respect to the pilot pressure circuit shut-off valve, wherein the switching mode as line power sale configuration to either the manual mode for operating the air cylinder by an auxiliary air which is generated by another auxiliary pressure source and the pressure source, the mode switching Supplies the pressurized air from the pressure source as the pilot pressure to the circuit shut-off valve in the automatic mode and shuts off the flow of the auxiliary air, and when the automatic mode is switched to the manual mode, The pilot pressure is reduced to the atmospheric pressure level, and auxiliary air from the auxiliary pressure source is supplied to, discharged from, and stopped from the air cylinder .

According to a second aspect of the present invention, the mode switching valve has a valve body accommodating hole therein and is provided with a plurality of connection ports respectively connected to the auxiliary pressure source and the air cylinder via pipes. A casing, an operation valve body that is rotatably provided in a valve body accommodation hole of the valve casing, and selectively communicates and blocks the plurality of connection ports according to a rotation operation; a valve body accommodation hole of the valve casing; An atmospheric chamber formed between the operation valve body and maintained in an atmospheric pressure state, and located between the operation valve body and each connection port and provided in the valve casing, and each connection port and operation valve body And a plurality of sealing bodies that hermetically seal with respect to the atmosphere chamber.

According to a third aspect of the present invention, the seal body includes a cylindrical seat member having an inner peripheral side that is a passage hole communicating with the connection port and an outer peripheral side that is airtightly fitted to the valve casing, and the operation valve body. And a corrugated washer provided between the seat member and the valve casing for elastically urging the seat member toward the operation valve body.

According to a fourth aspect of the present invention, the mode switching valve projects from the valve casing outward in the radial direction of the valve body housing hole and is connected to the pressure source and pilot pressure is supplied to the circuit shut-off valve. A valve cylinder formed with a supply / exhaust port for supplying and discharging, and the supply / exhaust port provided movably in the valve cylinder is selectively selected from the atmosphere chamber and the inflow port in the valve casing. A movable valve body that communicates and blocks; and a biasing member that is provided between the valve cylinder and the movable valve body and biases the movable valve body toward the operation valve body in the valve body housing hole, The operation valve body is formed with a cam surface for driving the movable valve body against the urging member when being rotated.

As described above, according to the first aspect of the present invention, a circuit shut-off valve is provided between the air cylinder and the positioner, and the circuit shut-off valve and the air cylinder are branched from the air pipe connecting them. A mode switching valve is provided via the branched pipe , and the mode switching valve supplies pressurized air from a pressure source as a pilot pressure to the circuit shut-off valve in the automatic mode and shuts off the flow of auxiliary air; wherein when switching from the automatic mode to manual mode, supply and discharge auxiliary air by the auxiliary pressure source with reducing the pilot pressure to a level of atmospheric pressure to said air cylinder, since the structure you stopped, the mode switching valve When switching to the automatic mode, the pilot pressure supplied to the circuit cutoff valve through the mode switching valve is made higher than the set pressure to open the circuit cutoff valve, and the positioner Together can hold between the air cylinder in communication with, it can be blocked by the mode switching valve the flow of such auxiliary air for the air cylinders. Further, when switching the mode selector valve from the automatic mode to the manual mode by lowering the pilot pressure to the level of atmospheric pressure, it is possible to hold the state of being cut off between the positioner and the air cylinder in the circuit shut-off valve, Auxiliary air from the auxiliary pressure source can be supplied / discharged to / from the air cylinder, and supply / exhaust can be stopped, and the rod of the air cylinder can be extended and retracted in the manual mode.

Therefore, a circuit cutoff valve is provided between the air cylinder and the positioner, and a mode switching valve is provided between the circuit cutoff valve and the air cylinder via a branch pipe branched from the air pipe connecting the two. by, it is possible to selectively drive control air cylinder in an automatic mode and a manual mode, selection of mode, a switching operation or the like can be improved operability and simplified. And since it becomes unnecessary to attach a clutch mechanism etc. to an air cylinder, the whole apparatus can be reduced in size and installation space etc. can be ensured easily.

Moreover, when switching the mode selector valve to the automatic mode, by supplying pressurized air from the pressure source to the circuit shut-off valve as a pilot pressure, in communication with the space between the positioner and the air cylinder in the circuit shut-off valve While being able to hold | maintain, distribution | circulation of auxiliary air etc. with respect to an air cylinder can be interrupted | blocked by the mode switching valve. The blocking, when switching the mode selector valve from the automatic mode to the manual mode, by decreasing the pilot pressure to the circuit shut-off valve to a level of atmospheric pressure, the air passage between the positioner and the air cylinder in the circuit shut-off valve In addition, the auxiliary air from the auxiliary pressure source can be supplied to and discharged from the air cylinder, and the supply and discharge can be stopped.

In the invention according to claim 2 , since the mode switching valve is constituted by the valve casing, the operation valve body, the atmospheric chamber, and a plurality of seal bodies, it is connected to the auxiliary pressure source and the air cylinder via pipes, respectively. The plurality of connection ports can be selectively communicated and shut off according to the turning operation of the operation valve body, and supply / exhaust or stop control of auxiliary air to the air cylinder can be performed. And by providing a seal body located between the operation valve body and each connection port in the valve casing, the space between each connection port and the operation valve body can be sealed airtight to the atmosphere chamber, The occurrence of air leakage from the mode switching valve can be suppressed, and the reliability and stability of the air cylinder driving device can be improved.

In the invention according to claim 3 , since the sealing body is constituted by a cylindrical seat member and a corrugated washer, the inner peripheral side becomes a passage hole communicating with the connection port, and the outer peripheral side is hermetically fitted to the valve casing. The combined cylindrical seat member can be pressed toward the operation valve body with a uniform urging force by a wave washer, and the gap between the operation valve body and the seat member can be hermetically sealed. Thereby, it is possible to satisfactorily suppress the occurrence of air leakage from the mode switching valve, and it is possible to ensure the reliability and stability of the air cylinder driving device.

Furthermore, according to the invention described in claim 4, the mode switching valve, the valve cylinder, a movable valve body and the biasing member, since the operating valve member is configured to form a cam surface, the operating valve body dose When operating, the movable valve element is moved in the valve cylinder by driving the movable valve element according to the shape of the cam surface against the biasing member, and the pilot pressure supply / exhaust port provided in the valve cylinder is It is possible to selectively communicate with or shut off either the atmosphere chamber in the valve casing or the inlet.

  As a result, when the supply / exhaust port communicates with the atmospheric chamber, the pilot pressure for the circuit shut-off valve can be reduced to the atmospheric pressure level, and the position between the positioner and the air cylinder can be kept shut by the circuit shut-off valve. it can. When the supply / discharge port communicates with the inflow port, pressurized air from a pressure source can be supplied as a pilot pressure to the circuit shut-off valve, and the circuit shut-off valve keeps the positioner and the air cylinder in communication. be able to.

  Hereinafter, an air cylinder driving device according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 13 of the accompanying drawings.

  In the figure, reference numeral 1 denotes a pressure source that is a supply source of pressurized air. The pressure source 1 is an air pump (air compressor) that generates pressurized air of, for example, about 0.1 to 0.7 MPa, or air. Consists of a stored air tank or the like. The pressure source 1 supplies pressurized air toward the air cylinder 3 described later into the air conduit 2.

  Reference numeral 3 denotes an air cylinder. The air cylinder 3 has a bottomed tubular tube 4, a piston 5 slidably fitted in the tube 4, and one end side fixed to the piston 5 and the other end side. And a rod 6 protruding to the outside of the tube 4. The inside of the tube 4 of the air cylinder 3 is defined by a piston 5 into a chamber A on the bottom side and a chamber B on the rod side.

  Here, the air cylinder 3 is configured such that the pressurized air from the pressure source 1 is supplied to and discharged from the chambers A and B in the tube 4 via a positioner 7 and air pipes 9A and 9B, which will be described later, so that the rod 6 is connected to the tube. 4 is expanded and contracted. The expansion / contraction amount of the rod 6 is variably controlled according to the supply / discharge amount of the pressurized air via the positioner 7.

  In addition, since such pressurized air is a compressible fluid (compressed air), the expansion / contraction amount of the rod 6 changes with the fluctuation | variation of the external force etc. which act on the air cylinder 3. FIG. However, the positioner 7 described later detects such expansion / contraction of the rod 6 and variably controls the air supply / discharge amount so that the rod 6 has an expansion / contraction amount corresponding to the command signal.

  Reference numeral 7 denotes a positioner for feedback-controlling the operation of the air cylinder 3. The positioner 7 has an input side connected to an air conduit 2 of the pressure source 1 via a pressure reducing valve 8, and an output side connected to an air pipe 9A as an air passage. , 9B are connected to the chambers A, B of the air cylinder 3.

  The positioner 7 supplies and discharges pressurized air supplied from the air conduit 2 of the pressure source 1 via the pressure reducing valve 8 to the air pipes 9A and 9B and the chambers A and B of the air cylinder 3 in accordance with a command signal described later. To do. That is, the positioner 7 variably controls the amount of air supplied and discharged from the pressure source 1 to the air cylinder 3 so that the rod 6 of the air cylinder 3 is expanded and contracted in a linear characteristic in proportion to the command signal. .

  A command device 10 outputs a command signal to the positioner 7. The command device 10 provides a command signal (a pilot signal or an electric signal by low-pressure air) corresponding to, for example, a dial turning operation or a lever tilting operation. Output to the positioner 7. Thereby, the positioner 7 controls the supply / discharge amount of the pressurized air so as to operate the air cylinder 3 with an expansion / contraction amount proportional to the value (command value) of the command signal.

  Reference numeral 11 denotes an automatic mode air pressure circuit, and the automatic mode air pressure circuit includes a pressure source 1, an air conduit 2, a positioner 7, a pressure reducing valve 8, air pipes 9A and 9B, and an air cylinder 3. Is done. The air pressure circuit 11 for the automatic mode is used when driving and controlling the air cylinder 3 in the automatic mode via the positioner 7 or the like.

  Reference numeral 12 denotes a pressure sensor for detecting pressurized air on the input side of the positioner 7. The pressure sensor 12 is located between the positioner 7 and the pressure reducing valve 8 and is connected in the middle of the air conduit 2. The pressure in the conduit 2 is detected.

  13A and 13B are pressure sensors for detecting pressurized air on the output side of the positioner 7, and these pressure sensors 13A and 13B are located between a circuit shut-off valve 14 and a positioner 7 which will be described later, and air pipes 9A and 9B. Are connected to each other, and the pressures in the air pipes 9A and 9B are individually detected.

  14 is a circuit shut-off valve provided in the air pressure circuit 11 for the automatic mode. The circuit shut-off valve 14 is located between the air cylinder 3 and the positioner 7 and is disposed in the middle of the air pipes 9A and 9B. For example, it comprises a pair of pilot operated check valves. The circuit shutoff valve 14 is opened and closed by a pilot pressure through a pilot pipe 19 described later, and communicates and shuts off the air pipes 9A and 9B before and after the circuit shutoff valve 14.

  That is, the circuit shut-off valve 14 keeps the communication between the positioner 7 and the air cylinder 3 via the air pipes 9A and 9B when the pilot pressure is higher than a predetermined set pressure. When the pilot pressure is reduced to the atmospheric pressure level and becomes lower than the set pressure, the air pipes 9A and 9B between the positioner 7 and the air cylinder 3 are shut off by the circuit shut-off valve 14, The air cylinder 3 is held in a state of being disconnected from the positioner 7.

  15 is a manual mode air pressure circuit connected to the air cylinder 3 in parallel with the automatic mode air pressure circuit 11, and the manual mode air pressure circuit 15 includes branch pipes 16A, 16B, supply pipe 17A, discharge pipe 17B, hand pump 18, mode switching valve 21 and the like. The air pressure circuit 15 is used when the air cylinder 3 is driven and controlled in the manual mode by the mode switching valve 21.

  Reference numerals 16A and 16B are branch pipes that form a branch passage together with the supply pipe 17A and the discharge pipe 17B. The branch pipes 16A and 16B are air at branch points 16a and 16b located between the air cylinder 3 and the circuit shut-off valve 14. Branching from the pipes 9A and 9B, the positioner 7 is connected to the air cylinder 3 in parallel.

  A mode switching valve 21 described later is provided between the branch pipes 16A and 16B and the supply pipe 17A and the discharge pipe 17B. The supply pipe 17A and the discharge pipe 17B are connected to the branch pipe 16A according to the switching operation of the mode switch valve 21. , 16B are communicated or blocked as described later.

  Reference numeral 18 denotes a hand pump as an auxiliary pressure source. The suction side of the hand pump 18 is connected to the discharge pipe 17B (or the atmosphere), and the discharge side is connected to the supply pipe 17A. The hand pump 18 generates necessary air pressure (auxiliary air), for example, when the operator manually rotates the handle 18A, and supplies and discharges the auxiliary air to and from the air cylinder 3 via the supply pipe 17A. is there.

  Reference numeral 19 is a pilot pipe for supplying and discharging pilot pressure to the circuit shut-off valve 14, and the pilot pipe 19 is connected to the conduit portion 2A of the air conduit 2 shown in FIG. . While the pilot pipe 19 communicates with the conduit portion 2A, pressurized air from the pressure source 1 is supplied to the circuit cutoff valve 14 via the pilot pipe 19, and the circuit cutoff valve 14 is connected to the air cylinder 3 and the positioner 7. Keep in communication with each other.

  On the other hand, when the pilot switch 19 switches a mode switching valve 21 described later from one of the automatic positions (a) to the switching positions (b) to (d) shown in FIG. Opened to the atmosphere, the pilot pressure on the circuit shut-off valve 14 is reduced to the atmospheric pressure level. Thereby, the circuit shut-off valve 14 keeps the state between the air cylinder 3 and the positioner 7 shut off.

  Reference numeral 21 denotes a mode switching valve for switching between an automatic mode and a manual mode. The mode switching valve 21 includes branch pipes 16A and 16B between the air cylinder 3 and the circuit shut-off valve 14 as shown in FIG. Is provided. As shown in FIGS. 2 to 13, the mode switching valve 21 includes a valve casing 22 described later, a valve cylinder 30, ball valve bodies 34 and 35, springs 37 and 38, an operation valve body 39, a valve shaft 42, and a lever 43. The air chamber 47, the seal body 48, and the like.

  Here, the mode switching valve 21 rotates the operation valve body 39 with a lever 43 described later, whereby the automatic position (a) and the switching positions (b), (c), (d) shown in FIG. It is switched to either. When the mode switching valve 21 is arranged at the automatic position (a), the automatic mode is selected, and when the mode switching valve 21 is switched to any one of the switching positions (b), (c), (d), so-called Manual mode is selected.

  22 is a valve casing constituting the outer shell of the mode switching valve 21. The valve casing 22 includes a bottomed cylindrical case 23 having a circular valve element housing hole 23A as shown in FIG. The lid 24 is configured to close the upper opening of the case 23. On the bottom 23B side of the case 23, there are formed an exhaust port 23C that is located on the center side and communicates with the outside air (atmosphere) in the valve body housing hole 23A, and connection ports 26B, 27B, 28B, and 29B described later. Has been.

  Further, as shown in FIG. 5, a stepped mounting hole 23D extending in the radial direction of the valve body receiving hole 23A is formed in the case 23, and a later-described valve cylinder 30 is detachably fitted into the mounting hole 23D. Installed. On the other hand, an insertion hole 24A into which a later-described valve shaft 42 is rotatably inserted is formed on the center side of the lid 24 as shown in FIG.

  The lid 24 is detachably fastened to the case 23 using bolts 25, 25,... As shown in FIG. 3, with the valve body accommodation hole 23A of the case 23 closed from the outside (upper side). Yes. In addition, a total of four engagement holes 24B, 24C, 24D, and 24E are formed on the back surface (the surface facing the valve body accommodation hole 23A) of the lid 24 as shown by the dotted lines in FIG. A ball plunger 41 (to be described later) is selectively engaged with and disengaged from the holes 24B to 24E.

  Reference numerals 26, 27, 28, and 29 denote a total of four stepped holes formed in the bottom 23B of the case 23. The stepped holes 26 to 29 are square with respect to the exhaust port 23C as shown in FIG. The lower end side of the case 23 is open to the bottom side of the case 23 as shown in FIG. And the large diameter hole part located in the upper part side of the stepped holes 26-29 is insertion hole part 26A, 27A, 28A, 29A in which each below-mentioned sheet | seat member 49 is inserted.

  Moreover, the taper hole part located in the lower part side of the stepped holes 26-29 becomes the connection ports 26B-29B of the branch pipes 16A, 16B, the supply pipe 17A, and the discharge pipe 17B constituting the branch passage. A branch pipe 16A is connected to 26B as shown in FIG. A supply pipe 17A is connected to the connection port 27B, a branch pipe 16B is connected to the connection port 28B, and a discharge pipe 17B is connected to the connection port 29B.

  Reference numeral 30 denotes a valve cylinder provided so as to protrude from the valve casing 22 in the radial direction. In the valve cylinder 30, as shown in FIGS. 23A in the radial direction of 23A, and a bottomed bottom formed on the back side (the other side) of the ball receiving hole 30B via an annular step 30C and having a smaller diameter than the ball receiving hole 30B. A hole 30D is provided.

  Further, on one side of the valve cylinder 30, a flange portion 30 </ b> E that protrudes radially outward and is formed in a substantially rectangular shape as a whole is integrally provided. The valve cylinder 30 is detachably fastened to the case 23 by bolts 31 and 31 with the open end 30A side fitted in the mounting hole 23D of the case 23.

  On the other hand, a pipe connecting portion 32 is integrally provided on the other side of the valve cylinder 30, and the pipe connecting portion 32 includes an air inlet 32A connected to the conduit portion 2A as shown in FIG. 19 is formed with a supply / discharge port 32B for supplying and discharging pilot pressure. The supply / exhaust port 32B is always in communication with the ball receiving hole 30B in the valve cylinder 30, and the air inlet 32A is a bottomed hole 30D located on the back side (the other side) of the valve cylinder 30. It is always in communication with the inside.

  Reference numeral 33 denotes an annular sheet fixedly provided in the valve cylinder 30. The annular sheet 33 is formed as a ring body using an elastic resin material having high wear resistance and is close to the opening end 30A of the valve cylinder 30. It is disposed in the ball receiving hole 30B at a position. The annular seat 33 slightly protrudes inward in the radial direction from the ball receiving hole 30B and can be separated from and contacted with a ball valve body 35 described later.

  That is, the ball valve body 35 described later is accommodated in the ball housing by elastically contacting or separating from the annular seat 33 in the ball housing hole 30B of the valve cylinder 30 as shown in FIGS. The inside of the hole 30 </ b> B is blocked or communicated with a valve body accommodation hole 23 </ b> A (atmospheric chamber 47 described later) of the valve casing 22.

  Reference numerals 34 and 35 denote ball valve bodies which are movably provided in the ball receiving holes 30B of the valve cylinder 30. The ball valve bodies 34 and 35 constitute a movable valve body together with a ball 36 which will be described later. Of the ball valve bodies 34 and 35, the ball valve body 34 is separated from (contacted or separated from) the stepped portion 30 </ b> C of the valve cylinder 30, so that the space between the ball receiving hole 30 </ b> B and the bottomed hole portion 30 </ b> D. The air inlet 32A is communicated and blocked with respect to the supply / discharge port 32B.

  Further, the ball valve body 35 is pushed (driven) via a ball 36 by a cam surface 40 of an operation valve body 39 described later. The ball valve body 35 moves in the length direction (axial direction) against the later-described springs 37 and 38 in the ball receiving hole 30B of the valve cylinder 30 so as to be separated from and in contact with the annular seat 33. is there.

  A ball 36 is located on the open end 30A side of the valve cylinder 30 and is movably provided in the ball receiving hole 30B. The ball 36 is formed by using a steel ball or the like in the same manner as the ball valve bodies 34 and 35. The ball valve body 35 is in contact with the ball housing hole 30B. The ball 36 transmits a pushing operation force by a cam surface 40 of the operation valve body 39 described later to the ball valve body 35 against the spring 38.

  Reference numeral 37 denotes a spring as an urging member provided between the bottomed hole portion 30D of the valve cylinder 30 and the ball valve body 34. The spring 37 separates the ball valve body 34 from the step portion 30C of the valve cylinder 30. The ball valve body 34 is always urged in the direction to be moved to allow the ball valve body 34 to contact (seat) the stepped portion 30C as shown in FIG.

  Reference numeral 38 denotes another spring as an urging member disposed between the ball valve body 34 and the ball valve body 35 in the ball housing hole 30B of the valve cylinder 30, and the spring 38 is disposed in the ball housing hole 30B. The ball valve body 35 is urged in a direction in which the ball valve body 35 is separated from the ball valve body 34, and the ball valve body 35 is brought into contact (sitting) with the annular seat 33 in the ball receiving hole 30B.

  When a pushing operation force by an operation valve body 39 (cam surface 40), which will be described later, is transmitted to the ball valve body 35 via the ball 36, the springs 37 and 38 are both bent and deformed, and the ball valve body 35 is shown in FIG. As shown in FIG. 4, the annular sheet 33 is allowed to be separated (seated). Thereby, the inside of the ball housing hole 30B of the valve cylinder 30 is switched from the shut-off state to the communication state with respect to the valve body housing hole 23A (the air chamber 47 described later) of the valve casing 22.

  Reference numeral 39 denotes an operation valve body rotatably provided in the valve body accommodation hole 23A of the valve casing 22, and the operation valve body 39 has a thick disk shape, and its outer peripheral surface is substantially D-shaped. The cam surface 40 is formed. Further, the lower side surface of the operation valve body 39 is formed as a flat sliding contact surface that comes into sliding contact with a later-described seat member 49, and a later-described valve shaft 42 is integrally formed on the upper surface side.

  In this case, the cam surface 40 includes a linear flat surface portion 40A formed by partially cutting (cutting) the outer peripheral surface of the operation valve body 39 as shown in FIGS. 5 and 7, and the flat surface portion. It is comprised by the circular arc surface part 40B extended in circular arc shape from the both sides of 40A. And the circular arc surface part 40B of the cam surface 40 is formed as an arc over the range of about 270-300 degree | times centering on the exhaust port 23C (axis line OO shown in FIG. 2), for example.

  Here, when the operation valve element 39 is rotated to the position shown in FIGS. 2 and 5, the cam surface 40 comes into contact with the ball 36 in the valve cylinder 30, and the ball 36 is in contact with the valve cylinder 30. It is allowed to project from the ball housing hole 30B into the case 23 (atmospheric chamber 47 described later) by about half. When the operation valve body 39 is rotated to the position shown in FIGS. 11 to 13, the arc surface portion 40 </ b> B of the cam surface 40 comes into contact with the ball 36 in the valve cylinder 30, and the ball 36 is accommodated in the ball of the valve cylinder 30. It is pushed (driven) so as to be pushed into the back side into the hole 30B.

  Further, a concave portion 39A having a small diameter is formed on the upper surface side of the operation valve body 39 at a position opposite to the flat surface portion 40A of the cam surface 40 across the valve shaft 42, and a ball plunger is provided in the concave portion 39A. 41 is attached. And this ball plunger 41 comprises a detent mechanism with engagement hole 24B, 24C, 24D, 24E of the cover body 24 shown to FIG. 2, FIG.

  That is, the ball plunger 41 engages with any of the engagement holes 24B to 24E of the lid body 24 when the operation valve body 39 is rotated about the axis OO, and the operation valve body 39 rotates. Give detent function to moving position. Thereby, the operation valve body 39 selectively switches the mode switching valve 21 to a total of four positions including the automatic position (a) and the switching positions (b) to (d) shown in FIG.

  Reference numeral 42 denotes a valve shaft integrally formed on the upper surface side of the operation valve body 39. The valve shaft 42 protrudes upward along the axis OO from the upper surface of the operation valve body 39 as shown in FIG. On the side, a lever mounting hole 42A is provided obliquely. A rod-like lever 43 that is gripped by an operator is attached to the lever attachment hole 42A of the valve shaft 42, for example.

  Here, the lever 43 is rotated to any one of the position of the line Oa, the position of the line Ob, the position of the line Oc, and the position of the line Od illustrated in FIG. 3 (a total of four positions). At this time, the ball plunger 41 is engaged with one of the engagement holes 24B, 24C, 24D, and 24E of the lid 24, and the mode switching valve 21 is switched to the automatic position (a) shown in FIG. The position is switched to any one of the positions (b) to (d).

  Further, the distal end side of the lever 43 is formed as a tapered pointed end portion 43A shown in FIGS. 2 and 3, and the pointed end portion 43A is formed with a plurality of marks (see FIG. 2) formed on the upper surface (outer side surface) of the lid body 24. (Not shown) has a function of notifying an operator or the like of the switching position of the mode switching valve 21.

  Reference numerals 44 and 45 denote two ventilation passages provided in the operation valve body 39. The ventilation passages 44 and 45 are spaced from each other to the left and right with respect to the exhaust port 23C as shown in FIG. The pair of straight passages extend in a direction substantially perpendicular to the flat surface portion 40A of the cam surface 40. The air passages 44 and 45 are hermetically closed at the opening side end facing the flat surface portion 40A of the cam surface 40 by using ball plugs 46 and 46 such as steel balls, and are blocked from an air chamber 47 to be described later. It is kept in the state.

  Further, the vent passages 44 and 45 are provided with a pair of port holes 44 </ b> A that are spaced apart in the length direction (front and rear directions) and open on the lower surface of the operation valve element 39 (sliding contact surface with respect to a sheet member 49 described later). 44B and port holes 45A and 45B are formed. These port holes 44A, 44B, 45A, 45B are arranged at positions that are square corners around the exhaust port 23C as shown in FIG. 5, and when the operation valve body 39 is rotated, As shown in FIGS. 12 and 13, the valve casing 22 is selectively communicated or blocked with any of the connection ports 26 </ b> B to 29 </ b> B.

  Reference numeral 47 denotes an atmospheric chamber formed between the valve body accommodating hole 23A of the case 23 and the operation valve body 39. The atmospheric chamber 47 is formed between the bottom 23B of the case 23 and the operation valve body 39 through the bottom 23B. The exhaust port 23C on the side always communicates with the inside, and the inside thereof is maintained in an atmospheric pressure state.

  48, 48,... Are a total of four seal bodies provided on the bottom 23B side of the case 23. Each of the seal bodies 48 includes a sheet member 49 and a corrugated washer 50, which will be described later, as shown in FIG. The connection ports 26B to 29B located on the lower side of the stepped holes 26 to 29 and the lower surface (sliding contact surface) of the operation valve body 39 are hermetically sealed.

  49, 49,... Are cylindrical sheet members constituting a part of the seal body 48. Each sheet member 49 is made of an elastic resin material such as polytetrafluoroethylene (PTFE) as shown in FIG. It is formed as a stepped cylinder, and the inner peripheral side thereof is a passage hole 49A extending through upward and downward. Further, the seat member 49 is integrally formed with an annular convex portion 49B on the upper end side thereof, and the annular convex portion 49B is in airtight sliding contact with the lower surface of the operation valve body 39.

  Here, as shown in FIGS. 2 and 6, the sheet member 49 is fitted and attached in the insertion holes 26 </ b> A, 27 </ b> A, 28 </ b> A, and 29 </ b> A of the stepped holes 26 to 29, respectively, The hole 49A communicates with the connection ports 26B to 29B individually. The outer peripheral side of the sheet member 49 is hermetically sealed between the insertion hole portions 26A, 27A, 28A, and 29A by a seal member such as an O-ring.

  50 are corrugated washers as elastic members that constitute the seal body 48 together with the sheet member 49, and each corrugated washer 50 has an insertion hole 27A, 29A (26A, 28A) as illustrated in FIG. Are arranged in an elastically deformed state between each bottom member and the seat member 49, and elastically bias the annular convex portion 49B of each seat member 49 toward the lower surface (sliding contact surface) of the operation valve body 39.

  Thereby, each seat member 49 is elastically pressed against the lower surface of the operation valve body 39 in a state where the annular convex portion 49B protrudes upward from the stepped holes 26 to 29 (the bottom surface of the case 23), and the valve casing 22 The inside air chamber 47 is hermetically sealed against the port holes 44A and 44B, the port holes 45A and 45B of the operation valve body 39, the passage hole 49A of the seat member 49, and the connection ports 26B to 29B.

  The air cylinder driving device according to the present embodiment has the above-described configuration, and the operation thereof will be described next.

  First, when the mode switching valve 21 is disposed at the automatic position (a), the pressurized air from the pressure source 1 is supplied to the inlet 32A of the valve cylinder 30 through the conduit portion 2A. At this time, the ball valve body 34 in the valve cylinder 30 is separated from the stepped portion 30C of the valve cylinder 30 as shown in FIG. 5, so that the bottomed hole portion 30D communicates with the ball receiving hole 30B. 32A is connected to the pilot pipe 19 through the supply / discharge port 32B.

  At this time, the ball valve body 35 in the valve cylinder 30 continues to be seated on the annular seat 33 in the ball accommodation hole 30B, and the ball accommodation hole 30B in the valve cylinder 30 is in contact with the atmospheric chamber 47 in the valve casing 22. And keep it shut off. In the valve casing 22, the air passages 44, 45 of the operation valve body 39 are blocked from the connection ports 26B, 27B, 28B, 29B as shown in FIG.

  For this reason, the branch pipes 16A and 16B, the supply pipe 17A and the discharge pipe 17B constituting the air pressure circuit 15 for manual mode are blocked from each other as shown in FIG. 1, for example, air leakage from the branch pipes 16A and 16B, etc. Can be almost completely prevented by the seal body 48 in the mode switching valve 21 or the like.

  At this time, the pressurized air from the pressure source 1 is supplied to the circuit cutoff valve 14 shown in FIG. 1 through the conduit portion 2A, the inlet 32A of the valve cylinder 30, the supply / discharge port 32B, and the pilot pipe 19. As a result, since the pilot pressure from the pilot pipe 19 is higher than the set pressure, the circuit shut-off valve 14 is opened and communicates between the positioner 7 and the air cylinder 3 via the air pipes 9A and 9B. Hold on.

  Thus, the air pressure circuit 11 for the automatic mode is selected by the mode switching valve 21 and the air from the pressure source 1 is supplied to the positioner 7 via the air conduit 2, and the positioner 7 receives a command signal from the command device 10. Accordingly, the amount of air supplied to and discharged from the air cylinder 3 can be remotely controlled, and the air cylinder 3 can be driven and controlled in an automatic mode via the positioner 7 or the like.

  Next, when the air cylinder 3 is operated in a so-called manual mode, for example, during maintenance or inspection of the air cylinder driving device or during assembly of the device, the mode switching valve 21 is switched from the automatic position (a) to the switching position ( Any one of b), (c), and (d) may be selectively switched.

  That is, when the lever 43 of the mode switching valve 21 is rotated by about 180 degrees from the position of the line Oa shown in FIG. 3 to the position of the line Oc, the mode switching valve 21 is moved to the automatic position shown in FIG. Switching from (a) to the switching position (c). At this time, the operation valve body 39 is rotated to the position shown in FIG. 11, and the ball 36 in the valve cylinder 30 is pushed into the back side of the ball receiving hole 30 </ b> B by the arc surface portion 40 </ b> B of the cam surface 40.

  Accordingly, the ball valve body 35 is separated from the annular seat 33 against the spring 38 in the ball receiving hole 30B, and the ball valve body 34 is seated on the step portion 30C against the spring 37. . As a result, the bottomed hole 30 </ b> D of the valve cylinder 30 is blocked from the ball housing hole 30 </ b> B, and the ball housing hole 30 </ b> B communicates with the atmosphere chamber 47 in the valve casing 22.

  For this reason, the supply / exhaust port 32B (pilot pipe 19) of the valve cylinder 30 is blocked from the inlet 32A on the pressure source 1 side, and communicates with the air chamber 47 in the valve casing 22 through the ball housing hole 30B. The circuit shutoff valve 14 shown in FIG. 1 shuts off the air pipes 9A and 9B between the air cylinder 3 and the positioner 7 because the pilot pressure through the pilot pipe 19 is reduced to the atmospheric pressure level. Thereby, drive control of the air cylinder 3 by what is called an automatic mode can be stopped or prohibited.

  However, in this case, the vent passages 44 and 45 of the operation valve body 39 in the valve casing 22 remain blocked from the connection ports 26B, 27B, 28B and 29B as shown in FIG. 16B, the supply pipe 17A, and the discharge pipe 17B are kept disconnected from each other.

  Next, when the lever 43 of the mode switching valve 21 is rotated by about 45 degrees from the position of the line Oc shown in FIG. 3 to the position of the line Ob, the mode switching valve 21 is moved to the switching position shown in FIG. Switching from (c) to switching position (b). At this time, the operation valve body 39 is rotated to the position shown in FIG. 12, and the air passage 44 of the operation valve body 39 communicates with the connection ports 27B and 26B via the port holes 44A and 44B. Further, the air passage 45 of the operation valve body 39 communicates with the connection ports 28B and 29B through the port holes 45A and 45B.

  In this case, the connection port 26B of the valve casing 22 is connected to the branch pipe 16A as shown in FIG. 4, and the connection port 27B is connected to the supply pipe 17A. The connection port 28B is connected to the branch pipe 16B, and the connection port 29B is connected to the discharge pipe 17B.

  As a result, the supply pipe 17A shown in FIG. 1 is connected to the branch pipe 16A via the mode switching valve 21 at the switching position (b), and the branch pipe 16B is connected to the discharge pipe 17B. Thereby, the auxiliary air from the hand pump 18 can be supplied to and discharged from the air cylinder 3 via the branch pipes 16A and 16B, and the air cylinder 3 can be driven in the manual mode.

  That is, for example, when the operator manually rotates the handle 18A of the hand pump 18, auxiliary air as necessary air pressure can be generated from the hand pump 18, and this auxiliary air is supplied to the supply pipe 17A, the branch pipe 16A, and the like. The rod 6 of the air cylinder 3 can be driven in the extending direction by supplying the air into the chamber A of the air cylinder 3 via the air cylinder 3.

  Next, when the lever 43 of the mode switching valve 21 is rotated by about 90 degrees from the position of line Ob shown in FIG. 3 to the position of line Od, the mode switching valve 21 is switched to the switching position shown in FIG. Switching from (b) to the switching position (d). At this time, the operation valve body 39 is rotated to the position shown in FIG. 13, and the air passage 44 of the operation valve body 39 communicates with the connection ports 26B and 29B via the port holes 44A and 44B. Further, the air passage 45 of the operation valve body 39 communicates with the connection ports 27B and 28B through the port holes 45A and 45B.

  As a result, the supply pipe 17A shown in FIG. 1 is connected to the branch pipe 16B via the mode switching valve 21 at the switching position (d), and the branch pipe 16A is connected to the discharge pipe 17B. Thereby, the auxiliary air from the hand pump 18 can be supplied into the chamber B of the air cylinder 3 via the supply pipe 17A, the branch pipe 16B, etc., and the rod 6 of the air cylinder 3 can be driven in the reduction direction.

  Thus, according to the present embodiment, the circuit shutoff valve 14 is provided in the middle of the air pipes 9A and 9B connecting the air cylinder 3 and the positioner 7, and between the air cylinder 3 and the circuit shutoff valve 14. Is provided with branch pipes 16A and 16B branched from the middle of the air pipes 9A and 9B, and between the supply pipe 17A and the discharge pipe 17B connected to the discharge side of the hand pump 18 and the branch pipes 16A and 16B Is provided with a mode switching valve 21 that is manually operated.

  Thereby, when the mode switching valve 21 is arranged at the automatic position (a), the pressurized air from the pressure source 1 can be supplied as pilot pressure to the circuit shut-off valve 14 by the pilot pipe 19, and the circuit shut-off valve 14 and the positioner 7 can be supplied. The communication with the air cylinder 3 can be maintained.

  At this time, the air flow to the air cylinder 3 through the branch pipes 16A and 16B can be blocked by the seal body 48 of the mode switching valve 21 and the occurrence of air leakage or the like can be almost completely prevented. As a result, when the air pressure circuit 11 for the automatic mode is selected by the mode switching valve 21, the air cylinder 3 can be driven and controlled in the automatic mode via the positioner 7 or the like.

  When the mode switching valve 21 is selectively switched from the automatic position (a) to the manual mode switching position (b), (c), (d), the pilot pressure for the circuit shut-off valve 14 is reduced to the atmospheric pressure level. By lowering, the air piping 9A, 9B between the positioner 7 and the air cylinder 3 can be shut off by the circuit shut-off valve 14. In this manual mode, the auxiliary air from the hand pump 18 can be supplied / discharged to / from the air cylinder 3 via the branch passages 16A, 16B or the supply / discharge can be stopped, and the rod 6 of the air cylinder 3 can be stopped. Can be stretched or shrunk manually.

  Further, since the mode switching valve 21 is constituted by the valve casing 22, the operation valve body 39, the atmospheric chamber 47, the plurality of seal bodies 48, etc., the branch pipe 16A on the bottom 23B side of the valve casing 22 (case 23), 16B, the connection ports 26B, 27B, 28B, 29B connected to the supply pipe 17A and the discharge pipe 17B can be selectively communicated and cut off according to the turning operation of the operation valve body 39, and the supply and discharge of auxiliary air to the air cylinder 3 can be performed. Or stop control can be performed smoothly.

  Then, on the bottom 23B side of the case 23, a total of four seal bodies 48, 48,... Are provided between the lower surface of the operation valve body 39 and the connection ports 26B, 27B, 28B, 29B. Since the sealing body 48 includes the cylindrical sheet member 49 and the corrugated washer 50, the space between the connection ports 26B, 27B, 28B, 29B and the operation valve body 39 can be hermetically sealed with respect to the atmospheric chamber 47. Air leakage from the mode switching valve 21 can be prevented almost completely.

  That is, the corrugated washer 50 elastically biases the annular convex portion 49B of the seat member 49 toward the lower surface (sliding contact surface) of the operation valve body 39, so that the annular convex portion 49B becomes the stepped holes 26 to 29. The sheet member 49 protruding upward from (the bottom surface of the case 23) can be pressed toward the lower surface of the operation valve body 39 with a substantially equal pressing force, and the operation valve body 39 and each sheet member 49 can be pressed. The space between the annular convex portion 49B can be hermetically sealed.

  The air chamber 47 in the valve casing 22 is hermetically sealed against the port holes 44A and 44B, the port holes 45A and 45B of the operation valve body 39, the passage hole 49A of the seat member 49, and the connection ports 26B to 29B. it can. Thereby, it is possible to satisfactorily suppress the occurrence of air leakage from the mode switching valve 21, and it is possible to improve the reliability and stability of the air cylinder driving device.

  Moreover, the mode switching valve 21 includes a valve cylinder 30, ball valve bodies 34 and 35, springs 37 and 38 as urging members, and the operation valve body 39 is formed with a cam surface 40. When the valve body 39 is rotated by the lever 43, the ball valve bodies 34 and 35 can be driven according to the shape of the cam surface 40 against the springs 37 and 38, and the ball valve bodies 34 and 35 within the valve cylinder 30. The pilot pressure supply / exhaust port 32 </ b> B provided in the valve cylinder 30 can be selectively communicated with or blocked from either the inflow port 32 </ b> A or the air chamber 47 in the valve casing 22.

  As a result, when the supply / exhaust port 32B communicates with the atmospheric chamber 47, the pilot pressure for the circuit shut-off valve 14 is reduced to the atmospheric pressure level, and the air piping 9A, 9B between the positioner 7 and the air cylinder 3 is shut off. The valve 14 can be held in a blocked state. Further, when the supply / exhaust port 32B communicates with the inflow port 32A, the pressurized air from the pressure source 1 can be supplied as a pilot pressure to the circuit shut-off valve 14, and the circuit shut-off valve 14 provides a space between the positioner 7 and the air cylinder 3. The communication state can be maintained.

  Therefore, according to the present embodiment, the circuit shutoff valve 14 is provided in the middle of the air pipes 9A and 9B connecting the air cylinder 3 and the positioner 7, and between the air cylinder 3 and the circuit shutoff valve 14. Can selectively drive and control the air cylinder 3 between the automatic mode and the manual mode by providing the mode switching valve 21 via the branch pipes 16A and 16B branching from the middle of the air pipes 9A and 9B. In addition, operability can be improved by simplifying mode selection, switching operation, and the like.

  And since it becomes unnecessary to attach a clutch mechanism etc., for example to the tube 4 side of the air cylinder 3, the whole apparatus can be reduced in size and an installation space etc. can be ensured easily.

  In the above embodiment, the case where the ball valve bodies 34, 35 and the like are provided in the valve cylinder 30 has been described as an example. However, the present invention is not limited to this. For example, a spool valve body or the like may be provided as a movable valve body so as to be slidable in the valve cylinder.

  Moreover, in the said embodiment, the case where the cam surface 40 of the operation valve body 39 was comprised by the flat surface part 40A and the circular arc surface part 40B was mentioned as an example, and was demonstrated. However, the present invention is not limited to this. For example, a cam surface including a plurality of uneven surfaces may be formed on the operation valve body.

It is a circuit block diagram which shows the air cylinder drive device by embodiment of this invention. It is a longitudinal cross-sectional view which shows the mode switching valve in FIG. 1 with a valve casing, an operation valve body, etc. It is the top view which looked at the mode switching valve of Drawing 2 from the upper part. FIG. 2 is a bottom view of the mode switching valve as viewed from below. It is sectional drawing which looked at the mode switching valve from the arrow VV direction in FIG. It is an expanded sectional view which looked at the valve casing etc. of the mode switching valve from the arrow VI-VI direction in FIG. It is a partially broken perspective view which shows the operation valve body in FIG. 2 as a single unit. It is a perspective view which shows the sheet | seat member in FIG. 2 as a single unit. It is an enlarged plan view which shows the waveform washer in FIG. 2 as a single unit. It is sectional drawing which looked at the waveform washer from the arrow XX direction in FIG. It is sectional drawing of the same position as FIG. 6 which shows the state which rotated the operation valve body to manual mode. FIG. 12 is an enlarged cross-sectional view illustrating a state in which the operation valve body is rotated from the position of FIG. 11 and the air passage is communicated with the connection port. FIG. 13 is an enlarged cross-sectional view illustrating a state in which the operation valve body is rotated in the direction opposite to that in FIG. 12 to connect the air passage to the connection port.

Explanation of symbols

1 Pressure Source 2 Air Conduit 2A Conduit 3 Air Cylinder 4 Tube 6 Rod 7 Positioner 8 Pressure Reducing Valve 9A, 9B Air Piping (Air Passage)
DESCRIPTION OF SYMBOLS 10 Command apparatus 11 Air pressure circuit for automatic mode 14 Circuit shut-off valve 15 Air pressure circuit for manual mode 16A, 16B Branch piping (branch passage)
17A Supply piping (branch passage)
17B Discharge piping (branch passage)
18 Hand pump (auxiliary pressure source)
19 Pilot piping 21 Mode switching valve 22 Valve casing 23 Case 23A Valve body accommodation hole 23B Bottom portion 23C Exhaust port 24 Cover body 26, 27, 28, 29 Stepped holes 26A, 27A, 28A, 29A Insertion hole portions 26B, 27B, 28B, 29B Connection port 30 Valve cylinder 32A Inlet port 32B Supply / discharge port 33 Annular seat 34, 35 Ball valve element (movable valve element)
37, 38 Spring (biasing member)
39 Operation valve body 40 Cam surface 41 Ball plunger 42 Valve shaft 43 Lever 44, 45 Air passage 44A, 44B, 45A, 45B Port hole 46 Ball stopper 47 Air chamber 48 Seal body 49 Sheet member 50 Wave washer

Claims (4)

A pressure source for supplying pressurized air, an air cylinder in which a rod is expanded and contracted by pressurized air from the pressure source, and an air amount provided between the air cylinder and the pressure source to be supplied to and discharged from the air cylinder. In an air cylinder driving device comprising a positioner that is variably controlled according to a command signal,
Between the air cylinder and positioner communicates between the positioner and the pneumatic cylinder when the pilot pressure supplied from the outside is higher than the set pressure, when the pilot pressure has dropped to the level of atmospheric pressure Provide a circuit shut-off valve that shuts off between the two,
Between the circuit shut-off valve and the air cylinder, a mode switching valve is provided via a branch pipe branched from an air pipe connecting the two,
The mode switching valve, and an automatic mode for operating the air cylinder by the pressurized air from the pressure source discharge sheet with respect to the circuit shut-off valve to the pilot pressure, generated in a separate auxiliary pressure source and the pressure source switching mode to one of a manual mode for operating the air cylinder and row cormorants configuration by an auxiliary air which is,
The mode switching valve supplies pressurized air from the pressure source as the pilot pressure to the circuit shut-off valve in the automatic mode and shuts off the flow of the auxiliary air to switch from the automatic mode to the manual mode. The air cylinder driving device is characterized in that when the pilot pressure is reduced to the atmospheric pressure level, the auxiliary air from the auxiliary pressure source is supplied to and discharged from the air cylinder and stopped . The mode switching valve includes a valve casing having a valve body housing hole therein and provided with a plurality of connection ports connected to the auxiliary pressure source and the air cylinder via pipes, and the valve body housing of the valve casing. A large valve is formed between an operation valve body that is rotatably provided in the hole and selectively communicates and blocks the plurality of connection ports according to a rotation operation, and a valve body accommodation hole of the valve casing and the operation valve body. An atmospheric chamber that is maintained in an atmospheric pressure state, and is provided between the operation valve body and each connection port and is provided in the valve casing, and the space between each connection port and the operation valve body with respect to the atmospheric chamber. The air cylinder drive device according to claim 1 , wherein the air cylinder drive device comprises a plurality of seal bodies that hermetically seal. The seal body has an airtight seal between a tubular seat member whose inner peripheral side is a passage hole communicating with the connection port and whose outer peripheral side is airtightly fitted to the valve casing, and between the operation valve body and the seat member. The air cylinder driving device according to claim 2 , further comprising a wave washer provided between the seat member and the valve casing and elastically biasing the seat member toward the operation valve body. The mode switching valve protrudes radially outward of the valve body housing hole from the valve casing and is connected to the pressure source, and a supply / discharge port for supplying and discharging pilot pressure to the circuit shut-off valve And a movable valve body that is movably provided in the valve cylinder and that selectively communicates and blocks the supply / exhaust port with either the air chamber in the valve casing or the inlet. A biasing member provided between the valve cylinder and the movable valve body and biasing the movable valve body toward the operation valve body in the valve body housing hole. The air cylinder driving device according to claim 2 or 3 , wherein a cam surface for driving the movable valve body against the biasing member when formed is formed.

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