Fluid injection or suction device

Abstract

To detect a position of a cylinder without use of mechanical or optical position detection means.SOLUTION: A fluid device 1 comprises: a cylinder 11; a piston 12 which partitions the interior of the cylinder into fluid chambers 19, 20; guides 13, 14 which support the piston 12 and guide movement of the cylinder, and have internal flow channels 26, 30 which communication-connect the fluid chambers 19, 20 to external pipings 37, 38; and nozzles 24, 25 which communicate with the fluid chambers 19, 20 respectively. The fluid device 1 comprises a short circuit flow channel 34 with throttling means, which short-circuits a flow channel communicating with a fluid pressure source 41 and a flow channel non-communicating with the same, in a flow channel from the external pipings 37, 38 to the nozzles 24, 25. The fluid device comprises closing means 72, 71, which close a proper place of a flow channel from the short-circuit flow channel 34 to the nozzles 24, 25 in a flow channel system non-communicating with the fluid pressure source 41 when the cylinder 11 is present at D1, D2 regulation positions, in the interior of the cylinder 11.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a fluid ejection or suction device for ejecting or suctioning a fluid. [Background technology]

[0002] A known fluid injection or suction device is one in which a nozzle communicating with the outside is provided in each of two spaces defined inside a cylinder by an inserted piston, and fluid is injected or sucked between the two spaces and the outside of the cylinder via the two nozzles, as described in Patent Document 1, for example. In this fluid injection or suction device, the piston is fixed, and during fluid injection, fluid is sent from a high-pressure source to one space, or during fluid suction, fluid is sucked from one space to a low-pressure source, and the change in volume between the two spaces at this time is used to move the cylinder. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-203111 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, in the fluid injection or suction device described in Patent Document 1, the cylinder can be moved at a constant speed if the amount of fluid injected or suctioned is constant, but it is conceivable that there may be situations in which it is necessary to reduce the cylinder movement speed for some reason.

[0005] The cylinder movement speed can be reduced by adjusting the pressure generated by the high-pressure source or the low-pressure source. However, if the pressure generated by the high-pressure source is reduced to reduce the cylinder movement speed while the fluid is being ejected, the amount of fluid ejected will decrease, while if the pressure generated by the low-pressure source is increased to reduce the cylinder movement speed while the fluid is being sucked, the amount of fluid sucked will decrease.

[0006] The cylinder movement speed can be reduced by increasing the maximum volume of the two spaces inside the cylinder or by reducing the nozzle diameter. However, increasing the maximum volume of the two spaces inside the cylinder increases the cylinder diameter, which limits the installation space, and reducing the nozzle diameter can reduce the amount of fluid sprayed or sucked. Furthermore, when the cylinder is operated while immersed in a fluid such as oil, it may be inappropriate to use a mechanical limit switch pressed by the cylinder or a sensor that optically detects the position of the cylinder to detect the position of the cylinder. As a means for detecting the position of the cylinder, it is conceivable to use a mechanical limit switch that is pressed by the cylinder when it moves to a specific position, an optical sensor that optically detects the position of the cylinder, etc. However, there are cases where it is inappropriate to use a mechanical switch, optical sensor, magnetic sensor, etc. as a position detection means, such as when the cylinder is operated while immersed in a fluid such as oil.

[0007] Therefore, in view of the above problems, the present invention aims to provide a fluid injection or suction device that can detect the cylinder position without using mechanical or optical position detection means, while suppressing an increase in the size of the cylinder and a decrease in the amount of fluid injected or suctioned, and while reducing the cylinder movement speed with a simple configuration. [Means for solving the problem]

[0008] The present invention provides a fluid injection or suction device that injects a fluid into a target space or suctions a fluid from the target space via a nozzle, the device comprising: a cylinder formed in a hollow tubular shape and having both end openings closed by closure members; a piston housed in the cylinder so as to be able to move back and forth relatively between the openings and dividing the interior of the cylinder into a first fluid chamber located on the side of the one end opening and a second fluid chamber located on the side of the other end opening; a guide that supports the piston and is slidably inserted into a through hole provided in at least one of the closure members to guide the cylinder so as to reciprocate; a first internal flow path that is disposed within the guide and connects the first fluid chamber to a first external pipe located outside the cylinder and the guide; a second internal flow path that is disposed within the guide and connects the second fluid chamber to a second external pipe located outside the cylinder and the guide; a first nozzle of the nozzles that connects the first fluid chamber to the target space; and a piston of the nozzles that connects the second fluid chamber to the target space. a second nozzle connected to the first external pipe; a first flow path system from the first external pipe to the first nozzle and a second flow path system from the second external pipe to the second nozzle; a throttle means disposed in the short-circuit flow path and throttling a flow rate of a fluid; a first closing means disposed in the first fluid chamber and opening and closing an appropriate position of a flow path in the first flow path system from the short-circuit flow path to the first nozzle depending on the position of the cylinder; and a second closing means disposed in the second fluid chamber and opening and closing an appropriate position of a flow path in the second flow path system from the short-circuit flow path to the second nozzle depending on the position of the cylinder. The piston is configured to be able to switch the connection destination of a pipe connected to a fluid pressure source that generates a predetermined pressure of fluid between the first external pipe and the second external pipe, and is configured such that at least when the cylinder is in a restricted state in which movement relative to the piston is restricted, the closing means substantially disconnects the nozzle from the short-circuit flow path in the flow path system to which the external pipe not connected to the fluid pressure source belongs. [Effects of the Invention]

[0009] The fluid injection or suction device of the present invention can detect the cylinder position without using mechanical or optical position detection means, while suppressing an increase in the size of the cylinder and a decrease in the amount of fluid injected or suctioned, and reducing the cylinder movement speed with a simple configuration. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic configuration diagram illustrating a fluid ejection or suction device according to a first embodiment. [Figure 2] 10A is an explanatory diagram showing the movement state of the moving cylinder in the direction D1 in the injection mode, and FIG. 10B is an explanatory diagram showing the D1 restriction state of the moving cylinder in the injection mode. [Figure 3] 10A and 10B are schematic diagrams illustrating a fluid ejection or suction device according to a second embodiment. [Figure 4] 10A and 10B are schematic diagrams illustrating a fluid ejection or suction device according to a third embodiment. [Figure 5] 10A and 10B are schematic diagrams illustrating a fluid ejection or suction device according to a fourth embodiment. [Figure 6] 10(a) and 10(b) are schematic diagrams showing other configuration examples in which a shunt flow path is arranged in the external piping system of a fluid ejection or suction device. [Figure 7] 10(a) and 10(b) are schematic diagrams illustrating the configuration of a fluid ejection or suction device according to a fifth embodiment. [Figure 8] 10(a) and 10(b) are schematic diagrams illustrating the configuration of a fluid ejection or suction device according to a sixth embodiment. [Figure 9] 10(a) and 10(b) are schematic diagrams illustrating a fluid ejection or suction device according to a seventh embodiment. [Figure 10] 10(a) to 10(c) are explanatory diagrams showing, in enlarged form, a part of the process of movement of the moving cylinder in the direction D1 in the injection mode of the device. [Figure 11] 13A and 13B are schematic diagrams illustrating a fluid ejection or suction device according to an eighth embodiment. [Figure 12] 10(a) to 10(c) are explanatory diagrams showing, in enlarged form, a part of the process of movement of the moving cylinder in the direction D1 in the injection mode of the device. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0012] First Embodiment Fig. 1 is a cross-sectional view showing a schematic configuration of a fluid ejection or suction device according to a first embodiment. Fig. 2(a) is an explanatory diagram showing a moving state of a moving cylinder in direction D1 in the ejection mode, and Fig. 2(b) is an explanatory diagram showing a D1 restricted state of the moving cylinder in the ejection mode. A fluid injection or suction device (hereinafter simply referred to as "fluid device") 1 is incorporated into a filtration device as a filter cleaning function, and is used, for example, to inject a fluid into the filter or to suction a fluid from the filter, thereby removing trapped matter that has adhered to the filter due to the filtration function of the filtration device. In general terms, the fluid device 1 comprises a piston-cylinder mechanism 2, an external piping system 3 connected to the piston-cylinder mechanism 2, and a control system 4.

[0013] (Piston-cylinder mechanism) The piston-cylinder mechanism 2 is a mechanism that injects a fluid by moving the fluid injection position or that sucks a fluid by moving the fluid suction position, and is disposed in a space E that is the target of fluid injection or suction (hereinafter referred to as the "target space"). The piston-cylinder mechanism 2 is mainly composed of a moving cylinder 11, a piston 12, a first guide 13, and a second guide 14.

[0014] Specifically, the movable cylinder 11 is formed as a hollow tube with a uniform cross section, and the piston 12, whose circumferential outline is formed following the inner circumferential surface of the movable cylinder 11, is inserted into the movable cylinder 11 between its two end openings so as to be relatively movable. The first guide 13 and the second guide 14 (piston rod) are formed as solid rods with a uniform cross section, and the area of ​​their circumferential outlines is smaller than that of the piston 12, and are connected to or integrally molded with the piston 12 so as to be as follows: That is, the first guide 13 extends outward from a portion of the inserted piston 12 facing one end opening of the movable cylinder 11 through that one end opening. Meanwhile, the second guide 14 extends outward from a portion of the inserted piston 12 facing the other end opening of the movable cylinder 11 through the other end opening. At least one of the first guide 13 and the second guide 14 (second guide 14 in the illustrated example) is fixed to an external structure F outside the piston-cylinder mechanism 2 (which may be the target space E; the same applies below), and the piston 12 is supported via at least one of the guides 13, 14. In this way, the piston-cylinder mechanism 2 is configured so that the moving cylinder 11 reciprocates while being guided by the guides 13, 14 while in sliding contact with the piston 12.

[0015] For ease of explanation, the movable cylinder 11 is assumed to be formed in a straight pipe shape, and the guides 13 and 14 extend linearly outward from the piston 12 inserted into the movable cylinder 11 through the rear end of both end openings of the movable cylinder 11, following the shape of the movable cylinder 11. As a result, the movable cylinder 11 moves linearly in a direction D1 from the piston 12 toward the first guide 13 or a direction D2 from the piston 12 toward the second guide 14. Note that the directions D1 and D2 can be selected from various directions, such as vertical or horizontal, depending on the installation posture of the piston-cylinder mechanism 2.

[0016] One end opening of the movable cylinder 11 is closed by a first closing member 15, and the other end opening of the movable cylinder 11 is closed by a second closing member 16. A first guide 13 passes through the first closing member 15 so as to be relatively movable, and a second guide 14 passes through the second closing member 16 so as to be relatively movable. The outer peripheral surfaces of the guides 13 and 14 slide against the inner peripheral surfaces of the through holes of the closing members 15 and 16, thereby guiding the movement of the movable cylinder 11.

[0017] An annular seal member 17, such as an O-ring, is held in a groove formed in a recess over the entire periphery on the inner periphery of the through hole of the first closing member 15, which faces the outer periphery of the first guide 13. An annular seal member 18 similar to the seal member 17 is held in a groove formed in a recess over the entire periphery on the inner periphery of the through hole of the second closing member 16, which faces the outer periphery of the second guide 14. These seal members 17, 18 are configured to contact the outer peripheries of the guides 13, 14 and maintain a liquid-tight or air-tight seal between the inside and outside of the moving cylinder 11.

[0018] The internal space of the movable cylinder 11, which is closed by the two closing members 15, 16, is divided into two spaces, a first fluid chamber 19 and a second fluid chamber 20, by the inserted piston 12. Specifically, the first fluid chamber 19 is defined by the piston 12, the first closing member 15, the movable cylinder 11, and the first guide 13, and the second fluid chamber 20 is defined by the piston 12, the second closing member 16, the movable cylinder 11, and the second guide 14. For example, if the cross-sectional outlines of the guides 13, 14 and the piston 12 do not overlap when viewed from direction D1 or direction D2, the first fluid chamber 19 and the second fluid chamber 20 will be cylindrical spaces.

[0019] In order to strictly divide the internal space of the moving cylinder 11 into two spaces, the first fluid chamber 19 and the second fluid chamber 20, an annular sealing member 21, such as an O-ring, is held in a groove recessed over the entire circumference of the outer peripheral surface of the piston 12 that faces the inner peripheral surface of the moving cylinder 11. This sealing member 21 is configured to slide against the inner peripheral surface of the moving cylinder 11 when the moving cylinder 11 moves along the guides 13, 14, and to maintain a liquid-tight or air-tight seal between the first fluid chamber 19 and the second fluid chamber 20.

[0020] A first communication passage 22 that communicates the first fluid chamber 19 with the target space E is formed in moving bodies such as the moving cylinder 11 and the closing members 15 and 16, which move relative to relatively stationary bodies such as the piston 12 and the guides 13 and 14. In the example shown, the first communication passage 22 is formed in the first closing member 15. In addition, a second communication passage 23 that communicates the second fluid chamber 20 with the target space E is formed in the moving body. In the example shown, the second communication passage 23 is formed in the second closing member 16.

[0021] The first communication passage 22 is provided with a hollow tubular first nozzle 24 that protrudes into the target space E, and similarly, the second communication passage 23 is provided with a hollow tubular second nozzle 25 that protrudes into the target space E. The first nozzle 24 and the second nozzle 25 either inject the fluid from the fluid chambers 19, 20 into the target space E or suck the fluid from the target space E into the fluid chambers 19, 20, depending on the type of fluid pressure source (described below) of the external piping system 3 connected to the piston-cylinder mechanism 2. The first nozzle 24 has a flow path cross-sectional area that is much smaller than the effective area of ​​the inner surface of the first fluid chamber 19 on which the fluid pressure in the first fluid chamber 19 acts in direction D1 (hereinafter referred to as the "first effective pressure-receiving area"). The second nozzle 25 has a flow path cross-sectional area that is much smaller than the effective area of ​​the inner surface of the second fluid chamber 20 on which the fluid pressure in the second fluid chamber 20 acts in direction D2 (hereinafter referred to as the "second effective pressure-receiving area"). For ease of explanation, it is assumed below that the first effective pressure-receiving area and the second effective pressure-receiving area are the common cylinder effective pressure-receiving area S, and that the flow path cross-sectional area of ​​the first nozzle 24 and the flow path cross-sectional area of ​​the second nozzle 25 are mutually common.

[0022] A first internal flow path 26 is formed inside the first guide 13, communicating between the first fluid chamber 19 and the external piping system 3. Specifically, the first internal flow path 26 extends from a first inner opening 27 that opens toward the first fluid chamber 19 near the piston 12 in the first guide 13, to a first outer opening 28 that opens toward the outside of the piston-cylinder mechanism 2 at an extended end of the first guide 13. A first connector 29 is provided in the first outer opening 28 to communicate between the first internal flow path 26 and the external piping system 3.

[0023] Furthermore, a second internal flow path 30 is formed inside the second guide 14, communicating between the second fluid chamber 20 and the external piping system 3. Specifically, the second internal flow path 30 extends from a second inner opening 31 that opens toward the second fluid chamber 20 near the piston 12 in the second guide 14, to a second outer opening 32 that opens toward the outside of the piston-cylinder mechanism 2 at an extended end of the second guide 14. A second connector 33 is provided in the second outer opening 32 to communicate between the second internal flow path 30 and the external piping system 3.

[0024] The piston-cylinder mechanism 2 configured as described above has a configuration almost identical to that of the fluid supply / suction means disclosed in Japanese Patent Application Laid-Open No. 2016-203111. However, this fluid supply / suction means differs from the piston-cylinder mechanism 2 in that it includes an orifice passage 34 drilled in the piston 12. The orifice passage 34 includes a short-circuit passage that connects (short-circuits) the first fluid chamber 19 and the second fluid chamber 20, and an orifice (restriction) that serves as a throttling means for throttling this short-circuit passage. The flow path cross-sectional area of ​​the orifice passage 34 is set to a value that is extremely small compared to the above-mentioned cylinder effective pressure-receiving area S.

[0025] The piston 12 also functions as a stopper that restricts the movement of the moving cylinder 11 by abutting against the second closing member 16 when the moving cylinder 11 moves in direction D1, or by abutting against the first closing member 15 when the moving cylinder 11 moves in direction D2. Here, the position of the first closing member 15 when the movement of the moving cylinder 11 in direction D1 is restricted is referred to as the D1 restricted position, and the state of the fluid device 1 when the movement of the moving cylinder 11 is restricted in this position is referred to as the D1 restricted state. Furthermore, the position of the second closing member 16 when the movement of the moving cylinder 11 in direction D2 is restricted is referred to as the D2 restricted position, and the state of the fluid device 1 when the movement of the moving cylinder 11 is restricted in this position is referred to as the D2 restricted state.

[0026] The orifice flow passage 34 has a first orifice opening 73 facing the first fluid chamber 19 and a second orifice opening 74 facing the second fluid chamber 20. In this example, the orifice openings 73, 74 open to each axial end face of the piston 12. Here, the axial direction refers to the direction in which the moving cylinder 11 reciprocates while being guided by the guides 13, 14. The first closing member 15 has a first closing portion 71 that closes the first orifice opening 73 when the movable cylinder 11 is in the D2 restricted state, thereby disconnecting the fluid chambers 19, 20. The second closing member 16 has a second closing portion 72 that closes the second orifice opening 74 when the movable cylinder 11 is in the D1 restricted state, thereby disconnecting the fluid chambers 19, 20. The closing portions 71, 72 in this example are closing surfaces that block the orifice openings 73, 74. The shape of the blocking members 15, 16, the position of the openings of the communicating passages 22, 23 facing the fluid chambers 19, 20, and the position of the inner openings 27, 31 are set so that even when the blocking members 15, 16 abut against the piston 12, the communicating passages 22, 23 and the internal flow paths 26, 30 remain connected via the fluid chambers 19, 20.

[0027] (External piping system) The external piping system 3 includes a first external piping 37, a second external piping 38, a pressure connecting pipe 39, a flow path switching valve 40, and a fluid pressure source 41. One end of the first external piping 37 is connected to the first connector 29, and the other end is connected to the flow path switching valve 40. One end of the second external piping 38 is connected to the second connector 33, and the other end is connected to the flow path switching valve 40. One end of the pressure connecting pipe 39 is connected to the flow path switching valve 40, and the other end is connected to the fluid pressure source 41. The flow path switching valve 40 is a flow path switching valve such as a three-way solenoid valve having a first port to which the first external pipe 37 is connected, a second port to which the second external pipe 38 is connected, and a pressure source port to which the pressure connection pipe 39 is connected. The three-way solenoid valve is configured to be able to close at least either the first port or the second port by external control. By switching the ports of the three-way solenoid valve, fluid can flow between the fluid pressure source 41 and the target space E via the piston-cylinder mechanism 2 in either the first flow path system or the second flow path system. Here, the first flow path system is made up of the first external piping 37, the first internal flow path 26, the first fluid chamber 19, the first communication path 22, and the first nozzle 24. In addition, the second flow path system is made up of the second external piping 38, the second internal flow path 30, the second fluid chamber 20, the second communication path 23, and the second nozzle 25.

[0028] Instead of using a three-way solenoid valve, two two-way solenoid valves may be used as the flow path switching valve 40. Specifically, the pressure connection pipe 39 connected to the fluid pressure source 41 may be a two-branch pipe, with one branch port of the two-branch pipe connected to the first external pipe 37 via a two-way solenoid valve, and the other branch port of the two-branch pipe connected to the second external pipe 38 via a two-way solenoid valve. By opening the two-way solenoid valve connected to the first external pipe 37 and closing the two-way solenoid valve connected to the second external pipe 38, the first flow path system allows fluid to flow between the fluid pressure source 41 and the target space E via the piston-cylinder mechanism 2. On the other hand, by closing the two-way solenoid valve connected to the first external pipe 37 and opening the two-way solenoid valve connected to the second external pipe 38, the second flow path system allows fluid to flow between the fluid pressure source 41 and the target space E via the piston-cylinder mechanism 2. In short, the flow path switching valve 40 can be of any type as long as it is an externally controllable solenoid valve that can enable fluid flow between the fluid pressure source 41 and the target space E via the piston-cylinder mechanism 2 in either the first flow path system or the second flow path system.

[0029] As the fluid pressure source 41, a high-pressure source is used when spraying fluid from the fluid chambers 19, 20 into the target space E through the nozzles 24, 25, while a low-pressure source is used when sucking fluid from the target space E into the fluid chambers 19, 20 through the nozzles 24, 25.

[0030] The high-pressure source generates a fluid at a pressure higher than the pressure in the target space E (hereinafter referred to as the "target space pressure") Ptgt. Specifically, the pressure generated by the high-pressure source is set to a pressure (Ptgt + Δp) that takes into account the flow path loss Δp from the high-pressure source to the nozzles 24 and 25 (first flow path system, second flow path system, etc.) relative to the target space pressure Ptgt. The high-pressure source may include, for example, a fluid storage tank that stores the fluid and a pump that pressurizes the fluid in this fluid storage tank to a constant level, and may further include a regulator, buffer tank, etc. to maintain a constant pressure. However, if the pressure (Ptgt + Δp) that takes into account the flow path loss Δp from the high-pressure source to the fluid chamber relative to the target space pressure Ptgt is lower than atmospheric pressure, the high-pressure source may be omitted and the pressure source port may be open to the atmosphere.

[0031] The low-pressure source generates a fluid at a pressure lower than the target space pressure Ptgt. Specifically, the pressure generated by the low-pressure source is set to a pressure (Ptgt-Δp) lower than the target space pressure Ptgt, taking into account flow path losses Δp from the nozzles 24, 25 to the low-pressure source (first flow path system, second flow path system, etc.). The low-pressure source may include, for example, a vacuum pump, and may further include a regulator, buffer tank, etc. to maintain a constant pressure. However, if the target space pressure Ptgt is higher than the pressure obtained by adding flow path losses Δp from the nozzles 24, 25 to the low-pressure source to atmospheric pressure, the low-pressure source may be omitted and the pressure source port may be open to the atmosphere.

[0032] (Control system) The control system 4 includes a first pressure detector 42 that detects the pressure P1 of the first flow path system, a second pressure detector 43 that detects the pressure P2 of the second flow path system, a third pressure detector 44 that detects the pressure P3 in the pressure connection pipe 39, and a controller 45. In this example, the first pressure detector 42 is installed in the first external pipe 37, and the second pressure detector 43 is installed in the second external pipe 38. The pressure detectors 42 to 44 function as proximity detectors that detect when the movable cylinder 11 has moved to the D1 restriction position and / or when the movable cylinder 11 has moved to the D2 restriction position. The controller 45 can switch the ports of the flow path switching valve 40 by outputting control signals based on the output signals from the pressure detectors 42 to 44. The control system 4 can be configured to include first and second pressure detectors 42, 43, or only the third pressure detector 44, depending on the drive conditions of the piston-cylinder mechanism 2.

[0033] The controller 45 includes a microcomputer having a processor such as a CPU (Central Processing Unit). This microcomputer has a ROM (Read Only Memory), a RAM (Random Access Memory), an input / output interface, and the like, which are communicatively connected to the processor via an internal bus. The controller 45 controls the operation of the fluidic device 1 through software processing in which the processor of the microcomputer reads an operation control program for the fluidic device 1 from the ROM into the RAM and executes it. However, this does not exclude the possibility that part or all of the operation control of the fluidic device 1 in the controller 45 is performed by a hardware configuration such as a relay sequence.

[0034] As described above, various fluids can be used as the fluid used for spraying or suction in the fluidic device 1 including the piston-cylinder mechanism 2, external piping system 3, and control system 4, depending on the application of the fluidic device 1. For example, in the case of cleaning applications, in addition to water, aqueous solutions of detergents, organic solvents, oils, etc., and even air and various gases can be used as the gas, in the case of painting applications, various paints can be used, and in the case of spraying applications, various spray liquids can be used. Note that when the fluid is a liquid, it is preferable that the viscosity is 0.1 cP to 1000 cP. The fluid device 1 can also be used in a manner in which the moving cylinder 11 is immersed in liquid and fluid is sprayed from the nozzles 24 and 25 to clean an object.

[0035] (Fluid ejection action) Next, referring to Figure 2, we will explain the injection mode, which is the operating mode of the fluid device 1 when injecting fluid from the fluid chambers 19, 20 into the target space E through the nozzles 24, 25. In the injection mode, as described above, a high-pressure source with a generated pressure PH higher than the target space pressure Ptgt and a delivery flow rate QH is used as the fluid pressure source 41. Hereinafter, it is assumed that the first flow path system and the second flow path system are filled with fluid. Furthermore, unless otherwise specified, the potential energy and pressure loss of the fluid are not taken into consideration.

[0036] FIG. 2(a) shows a state in which the movable cylinder 11 is moving in direction D1 in the injection mode. In this state, the controller 45 outputs a control signal to the three-way solenoid valve to close its second port in order to move the movable cylinder 11 in direction D1. Closing the second port of the three-way solenoid valve connects the high-pressure source and the first external pipe 37 via the first port of the three-way solenoid valve, thereby sending fluid from the high-pressure source to the first fluid chamber 19. When the fluid is sent from the high-pressure source to the first fluid chamber 19, the internal pressure of the first fluid chamber 19 increases, causing the fluid in the first fluid chamber 19 to be injected into the target space E through the first nozzle 24, increasing the volume of the first fluid chamber 19 and moving the movable cylinder 11 in direction D1. Then, the volume of the second fluid chamber 20 decreases, causing the fluid in the second fluid chamber 20 to be injected into the target space E through the second nozzle 25.

[0037] The jet flow rate of the first nozzle 24 is a value according to the pressure difference between the internal pressure of the first fluid chamber 19 and the target space pressure Ptgt. The internal pressure PA1 of the first fluid chamber 19 becomes equal to the generated pressure PH of the high-pressure source. The injection flow rate of the second nozzle 25 is a value according to the pressure difference between the internal pressure of the second fluid chamber 20 and the target space pressure Ptgt. The internal pressure PB1 of the second fluid chamber 20 is smaller than the internal pressure PA1 of the first fluid chamber 19 by the amount of the friction force R generated between the moving cylinder 11 and the piston 12 and between the closing members 15, 16 and the guides 13, 14. When the orifice passage 34 is provided, a minute flow rate q1 of fluid flows from the first fluid chamber 19 into the second fluid chamber 20 via the orifice passage 34. Therefore, the rate at which the volume of the first fluid chamber 19 increases is slower than when the orifice passage 34 is not provided. Strictly speaking, the friction force R generated when the moving cylinder 11 moves changes according to the speed of the moving cylinder 11. However, the change in the friction force R is sufficiently small compared to the force acting on the moving cylinder 11 based on the change in the internal pressure of the fluid chamber, and therefore can be ignored in calculations. As a result, the jet flow rate of the first nozzle 24 and the jet flow rate of the second nozzle 25 are almost the same whether or not the orifice flow path 34 is provided. In this way, in the fluid device 1, by providing the orifice flow path 34, when the moving cylinder 11 moves in the direction D1 in the injection mode, the speed of the moving cylinder 11 can be reduced without reducing the injection flow rate of the first nozzle 24 and the injection flow rate of the second nozzle 25, and without reducing the injection pressure of both nozzles.

[0038] 2(b) shows the D1 restricted state of the movable cylinder 11 in the injection mode. In this state, the movable cylinder 11 stops at the D1 restricted position, which maximizes the volume of the first fluid chamber 19 and minimizes the volume of the second fluid chamber 20, thereby stopping volume change. When the movable cylinder 11 stops at the D1 restricted position, fluid continues to be pumped from the high-pressure source to the first fluid chamber 19, so fluid injection from the first nozzle 24 continues. Meanwhile, the second orifice opening 74 is closed by the second closing portion 72, which stops the flow of fluid from the first fluid chamber 19 to the second fluid chamber 20 via the orifice flow path 34. Since there is no fluid flowing from the second external pipe 38 to the second fluid chamber 20, fluid injection from the second nozzle 25 stops.

[0039] When the controller 45 detects that the moving cylinder 11 has stopped at the D1 restriction position based on the output signal from any of the pressure detectors 42 to 44, it outputs a control signal to the three-way solenoid valve to close its first port in order to switch the moving direction of the moving cylinder 11 to direction D2. The case where the movable cylinder 11 is moved in the direction D2 in the injection mode is similar to the case where the movable cylinder 11 is moved in the direction D1, and therefore a detailed description thereof will be omitted. The method for detecting the position of the moving cylinder 11 based on the output signals from the pressure detectors 42 to 44 will be described later.

[0040] (Fluid suction action) When a low-pressure source with a generated pressure PL and suction flow rate QL lower than the target space pressure Ptgt is used as the fluid pressure source 41, the fluid device 1 can be operated in a suction mode in which fluid is sucked from the target space E through the nozzles 24 and 25 into the fluid chambers 19 and 20. It is clear that the fluid device 1 can be operated in the suction mode in the same way as in the injection mode, so a detailed explanation will be omitted here. In the fluid device 1, by providing the orifice flow path 34, when the moving cylinder 11 moves in the directions D1 and D2 in suction mode, the speed of the moving cylinder 11 can be reduced without reducing the suction flow rate of the first nozzle 24 and the suction flow rate of the second nozzle 25, and without reducing the injection pressure of both nozzles.

[0041] (Detection of cylinder position - when the fluid pressure source is a constant pressure source) ((Detection based on pressure changes)) When a constant pressure source is used as the fluid pressure source 41 (for example, when fluid in an air-pressurized tank is supplied to the piston-cylinder mechanism 2), the pressure P3 does not change even if the amount of fluid flow in the piston-cylinder mechanism 2 changes, for example, when the injection from the second nozzle 25 stops. As shown in Figure 2(b), when the movable cylinder 11 moves to the D1 restriction position, injection from the first nozzle 24 continues and injection from the second nozzle 25 stops. At this time, the pressure P1 in the first flow path system becomes equal to the supply pressure P3, and the pressure P2 in the second flow path system becomes equal to 0. Here, zero pressure means that the pressure becomes the ambient pressure, which is often atmospheric pressure. Therefore, a second pressure detector 43 capable of detecting the pressure P2=0 is installed, for example, at an appropriate position on the second external pipe 38. Based on the detection signal from the second pressure detector 43 indicating that the pressure P2=0, the controller 45 can detect that the movable cylinder 11 has moved to the D1 restriction position.

[0042] Conversely, when the movable cylinder 11 moves to the D2 restriction position, the spray from the first nozzle 24 stops and the spray from the second nozzle 25 continues. At this time, the pressure P2 in the second flow path system becomes equal to the supply pressure P3, and the pressure P1 in the first flow path system becomes 0. Therefore, a first pressure detector 42 capable of detecting the pressure P1=0 is installed, for example, at an appropriate position on the first external pipe 37. Based on a detection signal from the first pressure detector 42 indicating that the pressure P1 has become the ambient pressure, the controller 45 can detect that the movable cylinder 11 has moved to the D2 restriction position.

[0043] The same applies when sucking fluid from the target space E into the fluid chambers 19, 20. That is, by detecting pressure P2 = 0, it can be detected that the moving cylinder 11 has moved to the D1 restriction position, and by detecting pressure P1 = 0, it can be detected that the moving cylinder 11 has moved to the D2 restriction position.

[0044] ((Detection based on flow rate changes)) The fluid device 1 may be provided with first to third flow meters instead of the pressure detectors 42 to 44. That is, the fluid device 1 may be configured to detect that the moving cylinder 11 has reached the regulated position by detecting the flow rates F1 to F3 instead of detecting the pressures P1 to P3. When the movable cylinder 11 moves to the D1 restriction position and spraying from the second nozzle 25 stops, the flow rate F2 in the second flow path system becomes 0. Also, when the movable cylinder 11 moves to the D2 restriction position and spraying from the first nozzle 24 stops, the flow rate F1 in the second flow path system becomes 0. That is, when the fluid pressure source 41 is a constant pressure source, the controller 45 can determine that the movable cylinder 11 has moved to the D1 restriction position based on a detection signal from the second flow meter that detects the flow rate F2=0 in the second flow path system. Similarly, the controller 45 can determine that the movable cylinder 11 has moved to the D2 restriction position based on a detection signal from the first flow meter that detects the flow rate F1=0 in the first flow path system.

[0045] When the movable cylinder 11 reaches the D1 (or D2) restriction position, the spray from the second nozzle 25 (or the first nozzle 24) stops, and the flow rates F1 and F3 (or F2 and F3) decrease from the flow rates before the movable cylinder 11 reaches the D1 (or D2) restriction position. Therefore, the controller 45 can determine that the movable cylinder 11 has reached the D1 (or D2) restriction position based on information that the flow rate F1 (or F2) has decreased by a predetermined amount. The controller 45 can determine that the moving cylinder 11 has reached the D1 or D2 restriction position based on information related to the moving direction of the moving cylinder 11 and information that the flow rate F3 has decreased by a predetermined amount. The controller 45 can determine the moving direction of the moving cylinder 11 based on information related to the control state of the flow path switching valve 40, i.e., information on whether the flow path switching valve 40 is closing the first port or the second port.

[0046] ((Detection based on fluctuations in pump load)) When an electric pump is used as the fluid pressure source 41, the current flowing through the electric pump and the power consumed by the electric pump change according to the change in the flow rate and discharge pressure of the fluid discharged by the electric pump. Therefore, it is possible to detect that the movable cylinder 11 has reached each restriction position based on the change in the current value (or the change in the amount of power consumed). In this case, the control system 4 includes an ammeter that measures the amount of current flowing through the fluid pressure source 41 serving as an electric pump, or a watt-hour meter that measures the amount of power consumed by the fluid pressure source 41. The output signal of the ammeter or watt-hour meter is input to the controller 45.

[0047] If the fluid pressure source 41 is an electric pump serving as a constant pressure source, when the moving cylinder 11 reaches the D1 or D2 restriction position, the flow rate of the fluid discharged from the fluid pressure source 41 decreases. At this time, the load on the electric pump decreases, and the current value or power consumption decreases. Therefore, the controller 45 can determine that the moving cylinder 11 has reached the D1 or D2 restriction position based on information related to the moving direction of the moving cylinder 11 and information that the current value or power consumption flowing to the electric pump has decreased at a predetermined rate (decreased by more than a predetermined threshold value set in advance).

[0048] (Detection of cylinder position - When the fluid pressure source is a constant flow source) ((Detection based on pressure changes)) When a constant flow source (such as a plunger pump) that supplies a constant amount of fluid is used as the fluid pressure source 41, it is possible to detect that the moving cylinder 11 has moved to the D2 or D1 restriction position by detecting that the pressure P1 or P2 has reached zero, or by detecting that the pressures P2 and P3, or P1 and P3, have increased at a predetermined rate. For ease of explanation, it is assumed below that the nozzles 24, 25 are set to inject the same amount of fluid when the movable cylinder 11 is moving in direction D1 or direction D2. If we do not take into account pressure loss in the pipe and assume that the fluid density does not change, the pressure (dynamic pressure) in the pipe is proportional to the square of the flow rate, and the flow rate is proportional to the square root of the pressure (dynamic pressure). For example, when the movable cylinder 11 moves from the state shown in Fig. 2(a) to the D1 restriction position shown in Fig. 2(b), the spray from the second nozzle 25 stops. Then, because the fluid pressure source 41 is a constant flow rate pressure source, the first nozzle 24, which continues to spray, sprays the amount of fluid that the second nozzle 25 sprayed in addition to the amount of fluid that the first nozzle 24 sprayed while the movable cylinder 11 was moving. Because the first nozzle 24 sprays twice as much fluid as before, the pressures P1 and P3 increase fourfold.

[0049] Generally, when a constant flow rate pressure source is used as the fluid pressure source 41, a pressure relief valve or pressure regulating valve (a pressure reducing valve or a constant pressure valve) is used to prevent a sudden pressure rise in the flow path system. These valves are attached, for example, to the pressure connection pipe 39 or the first and second external pipes 37, 38. When a pressure relief valve or the like is attached to the pressure connection pipe 39, one valve is sufficient in the external piping system 3. When a pressure relief valve or the like is attached to the external pipes 37, 38, a pressure relief valve or the like is required for each external pipe, so two valves are required in the external piping system 3. Figure 1(b) shows an example of a pressure safety valve in which a relief valve 46 is attached to the pressure connection pipe 39. When a relief valve is used, a self-resetting valve is used. The secondary side of the relief valve 46 is connected to a location where the pressure becomes low, such as the pump inlet. The installation locations of other pressure safety valves and pressure adjustment valves are also the same as in Figure 1(b).

[0050] Even if a pressure relief valve or the like is installed to prevent a sudden rise in pressure in the flow path system, if the flow rate of the fluid ejected from the movable cylinder 11 suddenly decreases due to the closure of a flow path leading to one of the injection nozzles, the pressure in the flow path system to which the external piping connected to the fluid pressure source belongs will rise by about 20% even if the pressure relief valve or pressure adjustment valve operates after the flow rate in the other flow path system suddenly increases. Therefore, the controller 45 can determine that the movable cylinder 11 has reached the D1 restriction position based on information that the pressure P1 has increased at a predetermined rate (for example, 10%), and can determine that the movable cylinder 11 has reached the D2 restriction position based on information that the pressure P2 has increased at a predetermined rate (for example, 10%). Furthermore, the controller 45 can determine that the movable cylinder 11 has moved to one of the restriction positions based on information related to the direction of movement of the movable cylinder 11 and information indicating that the supply pressure P3 has increased at a predetermined rate. With this configuration, only one pressure detector is required to detect that the movable cylinder 11 has moved to each restriction position. Conversely, by setting the operating pressure of the pressure relief valve etc. so that the pressure relief valve etc. operates after the pressure increase of pressure P1, P3 (or P2, P3) is reliably detected, it becomes easier to detect that the moving cylinder 11 has moved to the D1 (or D2) restriction position. Alternatively, a pressure regulating valve of the type that increases the valve pressure when the flow rate on the secondary side of the valve increases is used. The fluid device 1 is equipped with a pressure detector that detects the pressure increase caused by the operation of the pressure regulating valve, and by inputting the detection signal of the pressure detector to the controller 45, the controller 45 can determine that the moving cylinder 11 has reached the D1 (or D2) restriction position based on this detection signal. If the constant flow source has a sufficient capacity, it is advantageous to attach a pressure regulating valve to the fluid device 1, since the injection pressure from the nozzle can be freely changed by using the pressure regulating valve.

[0051] The same applies when sucking fluid from the target space E into the fluid chambers 19, 20, but in the suction mode, a pressure drop rather than a pressure increase of the pressures P1, P3 (or P2, P3) is detected.

[0052] ((Detection based on flow rate changes)) The fluidic device 1 may include, instead of the pressure detectors 42 to 44, first to third flow meters that detect the flow rates F1 to F3. When the fluid pressure source 41 is a constant flow source, as in the case of a constant pressure source, the controller 45 can determine that the movable cylinder 11 has reached the D1 (or D2) restriction position based on the detection signal from the flow meter that detects the flow rate F2 = 0 (or F1 = 0).

[0053] ((Detection based on fluctuations in pump load)) If the fluid pressure source 41 is a constant flow source, the constant flow source maintains a constant flow rate even after the moving cylinder 11 reaches the D1 (or D2) restriction position, so the pressure P3 increases. If an electric pump is used as the fluid pressure source 41, the load on the electric pump increases. Therefore, the controller 45 can determine that the movable cylinder 11 has reached the D1 or D2 restriction position based on information regarding the movement direction of the movable cylinder 11 and information that the current value or power consumption flowing through the electric pump has increased at a predetermined rate.

[0054] (Detection of cylinder position - when the fluid pressure source is a general pump) When a general pump (e.g., a centrifugal pump) that is not configured to maintain constant discharge pressure and discharge flow rate is used as the fluid pressure source 41, it is possible to determine that the moving cylinder has reached each regulating position based on changes in pressure and flow rate. That is, the controller 45 can determine that the moving cylinder 11 has reached the D1 (or D2) restriction position based on the detection signals from the pressure detectors 42 and 43 that detect the pressure P2=0 (or P1=0). Furthermore, the controller 45 can determine that the movable cylinder 11 has reached the D1 (or D2) restriction position based on a detection signal from the flow meter that detects the flow rate F2=0 (or F1=0).

[0055] Here, when an electric pump that is not configured to maintain constant discharge pressure and discharge flow rate is used as the fluid pressure source 41, the electric pump discharges fluid at a pressure according to its performance. When the moving cylinder 11 reaches the D1 (or D2) restriction position, at least one of the electric pump's discharge pressure and discharge flow rate decreases depending on the configuration of the electric pump. At this time, the load on the electric pump decreases, and the current value or power consumption decreases. Therefore, the controller 45 can determine that the moving cylinder 11 has reached the D1 or D2 restriction position based on information related to the moving direction of the moving cylinder 11 and information that the current value or power consumption flowing through the electric pump has decreased at a predetermined rate.

[0056] When a general pump is used as the fluid pressure source 41, a pressure regulating valve may be provided in the external piping system 3 as a safety device, just as when a constant flow source is used. If the pressure condition is such that the pressure regulating valve operates, the load on the electric pump will increase. Therefore, the controller 45 can determine that the movable cylinder 11 has reached the D1 or D2 restriction position based on information related to the moving direction of the movable cylinder 11 and information indicating that the current value or power consumption flowing through the electric pump has increased at a predetermined rate.

[0057] (Detection of cylinder position - Summary) The main methods for detecting the cylinder position explained above can be summarized as follows:

[0058] TIFF0007810414000001.tif47158

[0059] According to this embodiment, even if the moving speed of the moving cylinder is reduced, it is possible to detect that the moving cylinder has moved to the restricted position (or to determine whether the moving cylinder is at the restricted position) without using a mechanical or optical position detection means.

[0060] Second Embodiment 3(a) and (b) are schematic diagrams illustrating a fluid injection or suction device according to a second embodiment. (a) is an explanatory diagram illustrating the movement of the moving cylinder in direction D1 in the injection mode, and (b) is an explanatory diagram illustrating the D1 restricted state of the moving cylinder in the injection mode. This embodiment is a modification of the first embodiment, and differs from the first embodiment in the orientation of the orifice openings 73 and 74 of the orifice flow path 34.

[0061] In the fluid device 1b, the first orifice opening 73 facing the first fluid chamber 19 of the orifice passage 34 drilled in the piston 12 opens to the outer peripheral surface of the first guide 13, and the second orifice opening 74 facing the second fluid chamber 20 of the orifice passage 34 opens to the outer peripheral surface of the second guide 14.

[0062] The first closing member 15 has a first closing portion 71 that closes the first orifice opening 73 when the movable cylinder 11 is in the D2 restricted state. The first inner opening 27 is disposed closer to the piston 12 than the first orifice opening 73. When in the D2 restricted state, the first inner opening 27 is not closed, and the first internal flow path 26 maintains communication with the first fluid chamber 19. The second closing member 16 has a second closing portion 72 that closes the second orifice opening 74 when the movable cylinder 11 is in the D1 restricted state. The second inner opening 31 is disposed closer to the piston 12 than the second orifice opening 74. When in the D1 restricted state, the second inner opening 31 is not closed, and the second internal flow path 30 maintains communication with the second fluid chamber 20 (FIG. 3(b)).

[0063] As an example, the piston-cylinder mechanism 2 shown in this example is provided with first and second large diameter portions 78, 79 at the axial ends of the guides 13, 14 on the piston 12 side, the outer diameters of which are larger than the outer diameters of other portions of the guides 13, 14 in the axial direction. The first inner opening 27 and the first orifice opening 73 open to the outer peripheral surface of the first large diameter portion 78. The second inner opening 31 and the second orifice opening 74 open to the outer peripheral surface of the second large diameter portion 79. The closing members 15, 16 have first and second receiving recesses 80, 81 that receive at least a portion of the axial direction of the large diameter portions 78, 79. The inner peripheral side surfaces of the receiving recesses 80, 81 that face the guides 13, 14 are the closing portions 71, 72. When the moving cylinder 11 rotates around its axis, the large diameter portions 78, 79 are formed in a cylindrical shape, and the receiving recesses 80, 81 are formed in an annular shape.

[0064] The first large diameter portion 78 functions as a stopper that determines the axial position of the movable cylinder 11 so that when the movable cylinder 11 is in the D2 restricted state, the first closing portion 71 closes the first orifice opening 73 but does not close the first inner opening 27. The second large diameter portion 79 functions as a stopper that determines the axial position of the movable cylinder 11 so that when the movable cylinder 11 is in the D1 restricted state, the second closing portion 72 closes the second orifice opening 74 but does not close the second inner opening 31.

[0065] 3(b), when the movable cylinder 11 moves to the D1 restriction position, the second orifice opening 74 is closed by the second closing portion 72, so that the fluid chambers 19 and 20 are not in communication with each other. The same applies when the movable cylinder 11 moves to the D2 restriction position. Therefore, this embodiment also provides the same effect as the first embodiment. That is, even if the cylinder movement speed is reduced, it is possible to detect that the moving cylinder has reached the restricted position (or to determine whether the moving cylinder is at the restricted position) without using a mechanical or optical position detection means.

[0066] Third Embodiment 4(a) and (b) are schematic diagrams illustrating the configuration of a fluid ejection or suction device according to a third embodiment, where (a) is an explanatory diagram illustrating the movement of the moving cylinder in direction D1 in the ejection mode, and (b) is an explanatory diagram illustrating the D1 restricted state of the moving cylinder in the ejection mode.

[0067] The fluid device 1c according to this embodiment differs from the first embodiment in that the short-circuit flow path that short-circuits the first flow path system and the second flow path system is formed via a short-circuit pipe 61 that appears outside the movable cylinder 11, instead of the orifice flow path 34, and a flow control valve 62 is provided in this short-circuit pipe 61. The flow control valve 62 is a throttle valve that can adjust the flow rate continuously by changing its throttle opening, and is an electric valve whose throttle opening can be controlled by a controller 45.

[0068] The short-circuit pipe 61 communicates between a connector 64 that communicates with the first fluid chamber 19 via a communication passage 63 and a connector 66 that communicates with the second fluid chamber 20 via a communication passage 65, and a flow rate adjustment valve 62 is disposed in this short-circuit pipe 61. In the fluid device 1c, this short-circuit pipe 61 communicates between components of a stationary body that is stationary relative to a moving body such as the movable cylinder 11, thereby short-circuiting the first flow path system and the second flow path system. In this example, by providing the short-circuit pipe 61 on the stationary body, the first fluid chamber 19 and the second fluid chamber 20 are communicated and short-circuited between the two flow path systems.

[0069] When the flow rate adjustment valve 62 disposed in the short-circuit pipe 61 opens at a predetermined throttle opening, the fluid flows at the minute flow rates q1 and q2 between the first flow path system and the second flow path system, similar to the orifice flow path 34. As a result, when the moving cylinder 11 moves in the jet mode, the speed of the moving cylinder 11 can be reduced without reducing the jet flow rate of the first nozzle 24 and the jet flow rate of the second nozzle 25, and without reducing the jet pressure of both nozzles. On the other hand, when the moving cylinder 11 moves in the suction mode, the speed of the moving cylinder 11 can be reduced without reducing the suction flow rate of the first nozzle 24 and the suction flow rate of the second nozzle 25, and without reducing the suction pressure of both nozzles. In the fluid device 1c, the speed of the moving cylinder 11 can be reduced by a desired amount by appropriately adjusting the throttle opening of the flow rate adjusting valve 62.

[0070] The fluid device 1c includes a first closing portion 84 that closes the opening 82 of the communication passage 63 facing the first fluid chamber 19 when the movable cylinder 11 is in the D2 restricted state. The fluid device 1c includes a second closing portion 85 that closes the opening 83 of the communication passage 65 facing the second fluid chamber 20 when the movable cylinder 11 is in the D1 restricted state. In this example, the communication passages 63, 65 are formed in the closing members 15, 16. Closure portions 84, 85 are formed in appropriate positions on the piston 12 opposite the openings 82, 83.

[0071] The closing members 15, 16 have first and second protruding portions 35, 36, parts of which protrude toward the fluid chambers 19, 20. The openings 82, 83 open to the tip surfaces (axial end surfaces) of the protruding portions 35, 36. The closing portions 84, 85 are closing surfaces arranged on each surface of the piston 12 in the axial direction. In the D2 restricted state, the first communication passage 22 and the first internal flow path 26 maintain communication with the first fluid chamber 19. The amount of protrusion of the first protrusion 35 is set so that, when the moving cylinder 11 is in the D2 restricted state, the opening 86 through which the first communication passage 22 faces the first fluid chamber 19 and the first inner opening 27 are not blocked by the first blocking member 15. In other words, the first protrusion 35 functions as a stopper that restricts the axial position of the moving cylinder 11 so as not to close the opening 86 and the first inner opening 27 in the D2 restricted state.

[0072] In the D1 restricted state, the second communication passage 23 and the second internal flow path 30 maintain communication with the second fluid chamber 20 (FIG. 4(b)). The amount of protrusion of the second protrusion 36 is set so that, when the moving cylinder 11 is in the D1 restricted state, the opening 87 through which the second communication passage 23 faces the second fluid chamber 20 and the second inner opening 31 are not blocked by the second blocking member 16. In other words, the second protrusion 36 functions as a stopper that restricts the axial position of the moving cylinder 11 so as not to close the opening 87 and the second inner opening 31 in the D1 restricted state.

[0073] In this embodiment, when the moving cylinder 11 is in the D1 or D2 restricted state, the flow of fluid between the first fluid chamber 19 and the second fluid chamber 20 via the short-circuit pipe 61 is stopped. In this embodiment, as in the first embodiment, even if the cylinder movement speed is reduced, it is possible to detect that the moving cylinder has moved to the restricted position (or to determine whether the moving cylinder is in the restricted position) without using a mechanical or optical position detection means.

[0074] Fourth Embodiment 5(a) and 5(b) are schematic diagrams illustrating a fluid ejection or suction device according to a fourth embodiment, where (a) is an explanatory diagram illustrating a state in which the moving cylinder moves in direction D1 in the ejection mode, and (b) is an explanatory diagram illustrating a state in which the moving cylinder is restricted in D1 in the ejection mode. In the fluid device 1d according to this embodiment, the short-circuit flow path that short-circuits the first flow path system and the second flow path system is formed via a short-circuit pipe 61 that appears outside the movable cylinder 11, instead of the orifice flow path 34, and differs from the first embodiment in that a flow control valve 62 is provided in this short-circuit pipe 61. The flow control valve 62 is a throttle valve that can adjust the passing flow rate steplessly by changing its throttle opening, and is an electric valve whose throttle opening can be controlled by a controller 45.

[0075] The short-circuit pipe 61 communicates between the first external pipe 37 and the second external pipe 38, and a flow control valve 62 is disposed in this short-circuit pipe 61. In the fluid device 1d, this short-circuit pipe 61 communicates between components of moving bodies such as the movable cylinder 11, thereby short-circuiting the first flow path system and the second flow path system.

[0076] When the flow rate adjustment valve 62 disposed in the short-circuit pipe 61 opens at a predetermined throttle opening, the fluid flows at the minute flow rates q1 and q2 between the first flow path system and the second flow path system, similar to the orifice flow path 34. As a result, when the moving cylinder 11 moves in the jet mode, the speed of the moving cylinder 11 can be reduced without reducing the jet flow rate of the first nozzle 24 and the jet flow rate of the second nozzle 25, and without reducing the jet pressure of both nozzles. On the other hand, when the moving cylinder 11 moves in the suction mode, the speed of the moving cylinder 11 can be reduced without reducing the suction flow rate of the first nozzle 24 and the suction flow rate of the second nozzle 25, and without reducing the suction pressure of both nozzles.

[0077] In the fluid device 1d, the speed of the moving cylinder 11 can be reduced by a desired amount by appropriately adjusting the throttle opening of the flow rate adjusting valve 62. The fluid device 1d includes a first closing portion 84 that closes an opening 86 of the first communication passage 22 facing the first fluid chamber 19 when the movable cylinder 11 is in the D2 restricted state. The fluid device 1d includes a second closing portion 85 that closes an opening 87 of the second communication passage 23 facing the second fluid chamber 20 when the movable cylinder 11 is in the D1 restricted state. Closures 84,85 are positioned on piston 12 opposite openings 86,87.

[0078] The closing members 15, 16 have first and second protruding portions 35, 36, parts of which protrude toward the fluid chambers 19, 20. The openings 86, 87 open to the tip surfaces (axial end surfaces) of the protruding portions 35, 36. The closing portions 84, 85 are closing surfaces arranged on each surface of the piston 12 in the axial direction.

[0079] In the D2 restricted state, the first internal flow path 26 maintains communication with the first fluid chamber 19. The protrusion amount of the first protrusion 35 is set so that the first inner opening 27 is not blocked by the first blocking member 15 when the moving cylinder 11 is in the D2 restricted state. In other words, the first protrusion 35 functions as a stopper that restricts the axial position of the moving cylinder 11 so as not to close the first inner opening 27 in the D2 restricted state. In the D1 restricted state, the second internal flow path 30 maintains communication with the second fluid chamber 20 (FIG. 5(b)). The amount of protrusion of the second protrusion 36 is set so that the second inner opening 31 is not blocked by the second blocking member 16 when the moving cylinder 11 is in the D1 restricted state. In other words, the second protrusion 36 functions as a stopper that restricts the axial position of the moving cylinder 11 so as not to close the second inner opening 31 in the D1 restricted state.

[0080] (Detection of cylinder position - when the fluid pressure source is a constant pressure source) In this embodiment, since the short-circuit pipe 61 is disposed between the external pipes 37 and 38, the flow path system from the pressure connection pipe 39 to the fluid chambers 19 and 20 is not completely blocked. Therefore, even if the fluid device 1d is in the D1 and D2 restricted state, the pressures P2 and P1 cannot be reduced to zero due to its structure (i.e., only the pressures in the communicating passages 23 and 22 become zero). At this time, the pressures indicated by the pressure detectors 42 to 44 are P1 = P2 = P3, ignoring the pipe resistance. For this reason, if the fluid pressure source 41 is a constant pressure source, it is not possible to detect that the moving cylinder 11 has moved to the D1, D2 restriction positions based on the pressures P1 to P3.

[0081] When the movable cylinder 11 moves to the D1 (or D2) restriction position, the flow rate F2 in the second flow path system becomes 0 (or the flow rate F1 in the first flow path system becomes 0). Therefore, in this embodiment, as in the first embodiment, the controller 45 can determine that the movable cylinder 11 has reached the D1 (or D2) restriction position based on a detection signal from a flow meter that detects the flow rate F2 = 0 (or F1 = 0).

[0082] When the moving cylinder 11 reaches the D1 (or D2) restriction position, the flow rate of the fluid discharged from the fluid pressure source 41 decreases. When an electric pump, which is a constant pressure source, is used as the fluid pressure source 41, the situation is the same as in the first embodiment. That is, the controller 45 can determine that the moving cylinder 11 has reached the D1 or D2 restriction position based on information related to the moving direction of the moving cylinder 11 and information that the current value or power consumption flowing through the electric pump has decreased at a predetermined rate.

[0083] (Detection of cylinder position - When the fluid pressure source is a constant flow source) This configuration differs from the first embodiment in that the pressures P1 and P2 cannot be set to zero. However, if the fluid pressure source 41 is a constant flow source, a pressure relief valve or a pressure adjustment valve is attached to the external piping system 3, as described in the first embodiment. Therefore, in this embodiment, the controller 45 can determine that the moving cylinder 11 has reached the D1 (or D2) restriction position based on information that the pressure P1 (or P2) has increased at a predetermined rate. Also, the controller 45 can determine that the moving cylinder 11 has reached the D1 or D2 restriction position based on information related to the movement direction of the moving cylinder 11 and information that the pressure P3 has increased at a predetermined rate. It is not necessary to completely close the openings 86, 87 of the communication passages 22, 23 in each regulated state. It is sufficient that the openings 86, 87 are closed to an extent that allows the flow rate to be changed to a level that allows pressure changes such as P3 to be detected.

[0084] Furthermore, when the fluid pressure source is a constant flow source, the controller 45 can determine that the movable cylinder 11 has reached the D1 (or D2) restriction position based on information indicating that the flow rate F2 of the second flow path system has become 0 (or the flow rate F1 of the first flow path system has become 0).

[0085] Furthermore, if the fluid pressure source 41 is an electric pump serving as a constant flow source, when the moving cylinder 11 moves to the D1 (or D2) restriction position, a constant flow rate is maintained and the pressure P3 increases, so the load on the electric pump increases. Therefore, the controller 45 can determine that the moving cylinder 11 has moved to the D1 or D2 restriction position based on information related to the moving direction of the moving cylinder 11 and information that the current value or power consumption flowing through the electric pump has increased at a predetermined rate.

[0086] (Detection of cylinder position - when the fluid pressure source is a general pump) If the fluid pressure source 41 is a general pump that is not configured to maintain constant discharge pressure and discharge flow rate, it is possible to detect that the movable cylinder 11 has reached the regulated position as follows.

[0087] In the piping configuration of this embodiment, the pressures P2 and P1 cannot be reduced to zero, so when the moving cylinder 11 reaches the D1 (or D2) restriction position, the pressures P1 = P2 = P3 (when piping resistance is ignored). Here, the fluid pressure source 41, which is a general pump, does not function to maintain a constant discharge pressure. Therefore, the pressures P1 to P3 rise above the state before the moving cylinder 11 reaches the D1 (or D2) restriction position. Therefore, the controller 45 can determine that the movable cylinder 11 has reached the D1 or D2 restriction position based on information regarding the movement direction of the movable cylinder 11 and information that any of the pressures P1, P2, and P3 has increased at a predetermined rate.

[0088] Furthermore, when the fluid pressure source 41 is a general pump, the controller 45 can determine that the movable cylinder 11 has reached the D1 (or D2) restriction position based on information indicating that the flow rate F2 of the second flow path system has become 0 (or the flow rate F1 of the first flow path system has become 0).

[0089] Furthermore, when the fluid pressure source 41 is a general electric pump, it is the same as the first embodiment. In other words, when the external piping system 3 is not provided with a pressure regulating valve, the controller 45 can determine that the movable cylinder 11 has moved to the D1 or D2 restriction position based on information regarding the movement direction of the movable cylinder 11 and information that the current value or power consumption flowing through the electric pump has decreased at a predetermined rate. Furthermore, when a pressure regulating valve is provided in the external piping system 3, the controller 45 can determine that the movable cylinder 11 has moved to the D1 or D2 restriction position based on information regarding the direction of movement of the movable cylinder 11 and information indicating that the current value or power consumption flowing through the electric pump has increased at a predetermined rate.

[0090] (Detection of cylinder position - Summary) The main methods for detecting the cylinder position explained above can be summarized as follows:

[0091] TIFF0007810414000002.tif52157

[0092] In this embodiment, even if the moving speed of the moving cylinder is reduced, it is possible to detect that the moving cylinder has moved to the regulated position (or to determine whether the moving cylinder is at the regulated position) without using a mechanical or optical position detection means.

[0093] [Modification of external piping system] 6(a) and 6(b) are schematic diagrams showing other configuration examples in which a shunt passage is arranged in the external piping system of a fluid ejection or suction device. In the fluid device 1, a short-circuit flow path that short-circuits the first flow path system and the second flow path system may be formed via two short-circuit pipes 61a and 61b that appear outside the movable cylinder 11, instead of the orifice flow path 34, and a first flow rate adjustment valve 62a may be disposed in the first short-circuit pipe 61a, and a second flow rate adjustment valve 62b may be disposed in the second short-circuit pipe 61b. The flow rate adjustment valves 62a and 62b are motor-operated valves similar to the flow rate adjustment valve 62.

[0094] 6(a), a first flow rate adjustment valve 62a is disposed in a first short-circuit pipe 61a that communicates with the pressure connecting pipe 39 and the first external pipe 37, and a second flow rate adjustment valve 62b is disposed in a second short-circuit pipe 61b that communicates with the pressure connecting pipe 39 and the second external pipe 38. Furthermore, for example, when two two-way solenoid valves 40a, 40b are used as the flow path switching valve 40 as described above, as shown in FIG. 6(b), a first flow rate adjustment valve 62a is disposed in the first short-circuit pipe 61a that communicates with the two-branch pipe that is the pressure connecting pipe 39 and the first external pipe 37, bypassing the two-way solenoid valve 40a. Similarly, a second flow rate adjustment valve 62b is disposed in the second short-circuit pipe 61b that communicates with the two-branch pipe that is the pressure connecting pipe 39 and the second external pipe 38, bypassing the two-way solenoid valve 40b.

[0095] When fluid communication between the fluid pressure source 41 and the target space E shown in FIG. 5 and the like is performed via the first flow path system, the second flow rate adjustment valve 62b opens at a predetermined throttle opening, allowing fluid to flow at minute flow rates q1 and q2 between the first flow path system and the second flow path system, similar to the orifice flow path 34. On the other hand, when fluid communication between the fluid pressure source 41 and the target space E is performed via the second flow path system, the first flow rate adjustment valve 62a opens at a predetermined throttle opening, allowing fluid to flow at minute flow rates q1 and q2 between the first flow path system and the second flow path system, similar to the orifice flow path 34. As a result, when the moving cylinder 11 (see FIG. 5 and the like) moves in the jetting mode, the speed of the moving cylinder 11 can be reduced without reducing the jetting flow rates of the first nozzle 24 and the second nozzle 25, and without reducing the jetting pressures of both nozzles. On the other hand, when the moving cylinder 11 moves in the suction mode, the speed of the moving cylinder 11 can be reduced without reducing the suction flow rate of the first nozzle 24 and the suction flow rate of the second nozzle 25, and without reducing the suction pressure of both nozzles.

[0096] As described in the first embodiment, the amount of speed reduction of the moving cylinder 11 is set according to the values ​​of the minute flow rates q1 and q2 of the orifice flow path 34, and the values ​​of the minute flow rates q1 and q2 vary according to the flow path cross-sectional area of ​​the orifice flow path 34. Therefore, by appropriately adjusting the aperture of the first flow control valve 62a, the amount of speed reduction can be set to a desired value for the movement of the moving cylinder 11 in direction D2 in the injection mode and for the movement of the moving cylinder 11 in direction D1 in the suction mode. On the other hand, by appropriately adjusting the aperture of the second flow control valve 62b, the amount of speed reduction can be set to a desired value for the movement of the moving cylinder 11 in direction D1 in the injection mode and for the movement of the moving cylinder 11 in direction D2 in the suction mode. As a result, the amount of speed reduction of the moving cylinder 11 can be set to different values ​​when the moving cylinder 11 moves in direction D1 and when the moving cylinder 11 moves in direction D2 in each of the injection mode and suction mode. As described above, the external piping system 3 of the fluid device 1d shown in the fourth embodiment (FIG. 5) can be replaced with the external piping system 3 shown in FIGS. 6(a) and 6(b). Furthermore, the movement of the movable cylinder 11 to the D1 or D2 restriction position can be detected by the method shown in the fourth embodiment.

[0097] Fifth Embodiment 7(a) and (b) are schematic diagrams illustrating a fluid injection or suction device according to a fifth embodiment. (a) is an explanatory diagram illustrating the movement of the moving cylinder in direction D1 in the injection mode, and (b) is an explanatory diagram illustrating the D1 restricted state of the moving cylinder in the injection mode. This embodiment is a modification of the fourth embodiment, and differs from the fourth embodiment in that, instead of closing the openings 86 and 87 of the communication passages 22 and 23, the inner openings 27 and 31 of the internal flow passages 26 and 30 are closed.

[0098] The fluid device 1e includes a first closing portion 71 that closes the first inner opening 27 when the movable cylinder 11 is in the D2 restricted state. The fluid device 1e includes a second closing portion 72 that closes the second inner opening 31 when the movable cylinder 11 is in the D1 restricted state. The closing portions 71, 72 are arranged at appropriate positions on the closing members 15, 16 facing the inner openings 27, 31. In this example, the closing portions 71, 72 are closing surfaces arranged on the inner peripheral surfaces of the through holes of the closing members 15, 16 facing the outer peripheral surfaces of the guides 13, 14.

[0099] In the D2 restricted state, the first communication passage 22 maintains communication with the first fluid chamber 19. The protrusion amount of the first protrusion 35 is set so that the first communication passage 22 is not blocked by the first closing member 15 when the moving cylinder 11 is in the D2 restricted state. In other words, the first protrusion 35 functions as a stopper that restricts the axial position of the moving cylinder 11 so as not to close the first communication passage 22 in the D2 restricted state. In the D1 restricted state, the second communication passage 23 maintains communication with the second fluid chamber 20 (FIG. 7(b)). The protrusion amount of the second protrusion 36 is set so that the second communication passage 23 is not blocked by the second blocking member 16 when the moving cylinder 11 is in the D1 restricted state. In other words, the second protrusion 36 functions as a stopper that restricts the axial position of the moving cylinder 11 so as not to close the second communication passage 23 in the D1 restricted state.

[0100] In this embodiment, the fact that the movable cylinder 11 has moved to the D1 or D2 restriction position can be detected by the method shown in the fourth embodiment. Here, sealing members 17 and 18 are arranged on the moving moving cylinder 11, and a predetermined clearance is provided between the closing members 15 and 16 and the guides 13 and 14. Even if a gap of the above-mentioned size exists, the closing portions 71 and 72 can close the inner openings 27 and 31 to an extent that the flow rate can be changed to a level that allows pressure changes such as P3 to be detected.

[0101] When operating the fluid device 1 in an injection mode in which the fluid in the fluid chambers 19, 20 is injected into the target space E, when the moving cylinder 11 is in the D1, D2 restricted state, it is more preferable to close the inner openings 27, 31 as shown in FIG. 7 (fifth embodiment) than to close the openings 86, 87 leading to the nozzles 24, 25 as shown in FIG. 5 (fourth embodiment). In the latter case, the fluid in the fluid chambers 19, 20 is discharged from the nozzles 24, 25, causing the pressure in the fluid chambers 19, 20 to approach zero more strongly. This allows the inner openings 27, 31 to be blocked more strongly. Conversely, when fluid is sucked from the target space E into the fluid chambers 19, 20, the fourth embodiment is more suitable than the fifth embodiment.

[0102] Sixth Embodiment 8(a) and (b) are schematic diagrams showing a fluid injection or suction device according to a sixth embodiment. (a) is an explanatory diagram showing the movement of the moving cylinder in direction D1 in the injection mode, and (b) is an explanatory diagram showing the D1 restricted state of the moving cylinder in the injection mode. This embodiment is a modification of the fifth embodiment, and differs from the fifth embodiment in the opening directions of the inner openings 27 and 31.

[0103] In the fluid device 1f, the first internal flow passage 26 opens into the first fluid chamber 19 through a first internal opening 27, which faces the axial direction and opens onto the axial end surface of the piston 12. The first internal flow passage 26 extends from the first external opening 28, through the inside of the first guide 13 and the inside of the piston 12, to the first internal opening 27. In the fluid device 1f, the second internal flow passage 30 opens into the second fluid chamber 20 through a second internal opening 31, which faces the axial direction and opens onto the axial end surface of the piston 12. The second internal flow passage 30 extends from the second external opening 32, through the interior of the second guide 14 and the interior of the piston 12, to the second internal opening 31.

[0104] The fluid device 1f includes a first closing portion 71 on the first closing member 15 that closes the first inner opening 27 when the movable cylinder 11 is in the D2 restricted state. The first closing portion 71 is a closing surface disposed on the tip end surface (axial end surface) of the first protruding portion 35. The fluid device 1f includes a second closing portion 72 on the second closing member 16 that closes the second inner opening 31 when the movable cylinder 11 is in the D1 restricted state. The second closing portion 72 is a closing surface disposed on the tip end surface (axial end surface) of the second protruding portion 36. When the moving cylinder 11 rotates, the protrusions 35 and 36 are formed in an annular shape.

[0105] In the D2 restricted state, the first communication passage 22 maintains communication with the first fluid chamber 19. The amount of protrusion of the first protrusion 35 is set so that the first communication passage 22 is not blocked by the piston 12 when the moving cylinder 11 is in the D2 restricted state. In other words, the first protrusion 35 functions as a stopper that restricts the axial position of the moving cylinder 11 so as not to close the first communication passage 22 in the D2 restricted state. In the D1 restricted state, the second communication passage 23 maintains communication with the second fluid chamber 20 (FIG. 8(b)). The amount of protrusion of the second protrusion 36 is set so that the second communication passage 23 is not blocked by the piston 12 when the moving cylinder 11 is in the D1 restricted state. In other words, the second protrusion 36 functions as a stopper that restricts the axial position of the moving cylinder 11 so as not to close the second communication passage 23 in the D1 restricted state.

[0106] In this embodiment, the inner openings 27, 31 are opened to the piston 12 so as to face the axial direction of the piston 12. Therefore, when closing the inner openings 27, 31, no force other than that in the movement direction (axial direction) is generated in the moving cylinder 11. Therefore, this mode of closing the inner openings 27, 31 is more preferable than the fifth embodiment. In this embodiment, the fact that the movable cylinder 11 has moved to the D1 or D2 restriction position can be detected by the method shown in the fourth embodiment.

[0107] Seventh Embodiment 9(a) and 9(b) are schematic diagrams showing the configuration of a fluid injection or suction device according to a sixth embodiment. (a) is an explanatory diagram showing the movement state of the moving cylinder in direction D1 in the injection mode, and (b) is an explanatory diagram showing the D1 restricted state of the moving cylinder in the injection mode. Figures 10(a) to 10(c) are partially enlarged views showing the process by which the device reaches the D1 restricted state. This embodiment is a modification of the sixth embodiment, and differs from the sixth embodiment in the way the inner openings 27 and 31 are closed.

[0108] In the fluid device 1g, first and second receiving recesses 92, 93 are recessed and formed on the end surface of the piston 12 facing the fluid chambers 19, 20 to receive and engage at least a portion (tip end) of the axial direction of the protrusions 35, 36. The protrusions 35, 36 and the receiving recesses 92, 93 are columnar in shape and have a predetermined cross-sectional shape (a cross-sectional shape cut along a plane perpendicular to the axial direction). In the fluid device 1g, the inner openings 27, 31 are located at the innermost portions of the receiving recesses 92, 93 and open in the axial direction. When the moving cylinder 11 rotates, the protrusions 35, 36 and the receiving recesses 92, 93 are formed in an annular shape. Here, the protrusions 35, 36 are arranged spaced apart on the outer circumferential side from the through holes of the closing members 15, 16. Therefore, gaps 94, 95 are formed between the guides 13, 14 and the protrusions 35, 36.

[0109] FIG. 10(a) (FIG. 9(a)) shows a state in which the second protrusion 36 and the second receiving recess 93 are separated. When the movable cylinder 11 moves in direction D1 and the tip of the second protrusion 36 reaches the second receiving recess 93 as shown in FIG. 10(b), the second internal flow path 30 and the second fluid chamber 20 are no longer in communication with each other, and the flow of fluid from the second internal flow path 30 toward the second fluid chamber 20 stops. When the movable cylinder 11 further moves in direction D1, the tip of the second protrusion 36 enters the second receiving recess 93. Finally, as shown in FIG. 10(c) (FIG. 9(b)), the second protrusion 36 fits into the second receiving recess 93 and the movable cylinder 11 stops at the D1 restriction position. In this way, the second protrusion 36 disconnects the second internal flow path 30 from the second fluid chamber 20 when the movable cylinder 11 is within a range from a position immediately before the D1 restriction position to the D1 restriction position. Furthermore, the tip surface of the second protrusion 36 functions as a closing means (closing surface) that abuts against the end of the second inner opening 31 to close it when the movable cylinder 11 is in the D1 restriction state. The second protrusion 36 functions as a stopper that restricts the axial position of the movable cylinder 11 so that the second fluid chamber 20 and the second communication passage 23 are connected in the D1 restriction state.

[0110] <effect> 10(b), when the second internal flow path 30 and the second fluid chamber 20 are not in communication with each other, the supply of fluid to the second fluid chamber 20 stops and the pressure in the second fluid chamber 20 becomes zero. On the other hand, because the fluid continues to be supplied to the first fluid chamber 19, the pressure in the first fluid chamber 19 remains high. Even if the pressure in the first fluid chamber 19 and the pressure in the second receiving recess 93 are substantially the same, the fluid pressure-receiving area in the axial direction is larger in the first fluid chamber 19 than in the second receiving recess 93, so the moving cylinder 11 continues to move to the D1 restriction position. As a result, after the second protrusion 36 reaches the second receiving recess 93 and before the D1 restriction state is reached, the second protrusion 36 pressurizes the fluid in the second receiving recess 93 or causes the fluid in the second receiving recess 93 to flow back into the second external piping 38. Therefore, the flow rate in the first external pipe 37 (portion P1) changes more significantly than when the second inner opening 31 is simply closed as in the sixth embodiment (FIG. 8) and the like.

[0111] Furthermore, the moving speed of the movable cylinder 11 decreases significantly after the second protruding portion 36 reaches the second receiving recess 93. That is, the moving speed of the movable cylinder 11 becomes slow because the moving cylinder 11 can only move once the fluid stored in the gap 95 leaks out of the gap 95 and is discharged from the second nozzle 25. In this way, the second protruding portion 36 and the second receiving recess 93 function as a kind of cushion, thereby preventing wear on the moving cylinder 11 and the piston 12. In particular, wear on the portions where they come into contact in the axial direction can be prevented.

[0112] The same applies to the shapes and actions of the components in the first flow path system when the moving cylinder 11 moves in the direction D2.

[0113] <Effects> In this embodiment, the fact that the movable cylinder 11 has moved to the D1 or D2 restriction position can be detected by the method shown in the fourth embodiment. In addition, in this embodiment, after the internal flow path and the fluid chamber become disconnected, a means (protrusion) is provided to pressurize the fluid in the external piping or to cause the fluid to flow back toward the external piping, so that the change in flow rate becomes larger and the pressure of P3 changes more significantly, thereby improving the detection sensitivity of the position of the moving cylinder 11. Furthermore, since the moving speed of the moving cylinder 11 drops suddenly from the position immediately before the D1 or D2 restricting position, wear on the piston-cylinder mechanism 2 can be prevented.

[0114] Eighth Embodiment 11(a) and 11(b) are schematic diagrams showing the configuration of a fluid injection or suction device according to a sixth embodiment. (a) is an explanatory diagram showing the movement state of the moving cylinder in direction D1 in injection mode, and (b) is an explanatory diagram showing the D1 restricted state of the moving cylinder in injection mode. (a) to 12(c) are partially enlarged views showing the process by which the device reaches the D1 restricted state. This embodiment is an example in which the configuration shown in the seventh embodiment, in which a fluid is pressurized or reversed, is applied to the first embodiment (FIG. 2).

[0115] In the fluid device 1h, first and second receiving recesses 92, 93 are formed as recesses on the end faces of the piston 12 facing the fluid chambers 19, 20, to receive and engage at least a portion (tip ends) of the axial direction of the protrusions 35, 36. The protrusions 35, 36 and the receiving recesses 92, 93 have a predetermined cross-sectional shape (a cross-sectional shape cut along a plane perpendicular to the axial direction) and are shaped to extend in the axial direction. In the fluid device 1h, the orifice openings 73, 74 of the orifice flow passage 34 are located at the innermost parts of the receiving recesses 92, 93 and open to face the axial direction. When the moving cylinder 11 rotates, the protrusions 35, 36 and the receiving recesses 92, 93 are formed in an annular shape. Furthermore, gaps 94 and 95 are formed between the guides 13 and 14 and the protrusions 35 and 36 .

[0116] FIG. 12(a) (FIG. 11(a)) shows a state in which the second protrusion 36 and the second receiving recess 93 are separated. When the movable cylinder 11 moves in direction D1 and the tip of the second protrusion 36 reaches the second receiving recess 93 as shown in FIG. 12(b), the orifice flow path 34 and the second fluid chamber 20 are no longer in communication with each other, and the flow of fluid from the first fluid chamber 19 to the second fluid chamber 20 stops. When the movable cylinder 11 further moves in direction D1, the tip of the second protrusion 36 enters the second receiving recess 93. Finally, as shown in FIG. 12(c) (FIG. 11(b)), the second protrusion 36 fits into the second receiving recess 93 and the movable cylinder 11 stops at the D1 restriction position. In this way, the second protrusion 36 disconnects the orifice flow path 34 from the second fluid chamber 20 when the movable cylinder 11 is within a range from a position immediately before the D1 restriction position to the D1 restriction position. Furthermore, the tip surface of the second protrusion 36 functions as a closing means (closing surface) that abuts against the end of the second orifice opening 74 to close it when the movable cylinder 11 is in the D1 restriction state. As shown in FIG. 11(b), the second protrusion 36 functions as a stopper that restricts the axial position of the movable cylinder 11 so that the second internal flow path 30 and the second communication passage 23 communicate with the second fluid chamber 20 in the D1 restriction state.

[0117] In this example, the second protrusion 36 pressurizes the fluid in the second receiving recess 93 toward the first fluid chamber 19 or causes the fluid in the second receiving recess 93 to flow back into the first fluid chamber 19, during the period from when the second protrusion 36 reaches the second receiving recess 93 until the D1 restricted state is reached. Therefore, the flow rate in the first external pipe 37 (portion P1) changes more significantly than when the second orifice opening 74 is simply closed as in the first embodiment (FIG. 2) or the like.

[0118] In this example, the moving speed of the movable cylinder 11 drops significantly after the second protruding portion 36 reaches the second receiving recess 93. That is, the moving speed of the movable cylinder 11 is low because the moving cylinder 11 can only move once the fluid stored in the gap 95 leaks out of the gap 95 and is discharged from the second nozzle 25. The same applies to the shapes and actions of the components in the first flow path system when the moving cylinder 11 moves in the direction D2.

[0119] In this embodiment, the fact that the movable cylinder 11 has moved to the D1 or D2 restriction position can be detected by the method shown in the first embodiment. In addition, in this embodiment, after one fluid chamber and the orifice flow path become disconnected, a means (protrusion) is provided to pressurize the fluid in the orifice flow path or to cause the fluid to flow back to the other fluid chamber, so that the change in flow rate becomes larger and the change in pressure of P3 becomes larger, thereby improving the detection sensitivity of the position of the moving cylinder 11. Furthermore, since the moving speed of the moving cylinder 11 drops suddenly from the position immediately before the D1 or D2 restricting position, wear on the piston-cylinder mechanism 2 can be prevented.

[0120] [Modification] The present invention has been specifically described above with reference to preferred embodiments. However, it is obvious that a person skilled in the art can adopt various modified embodiments as described below based on the basic technical idea and teachings of the present invention.

[0121] In the first to eighth embodiments described above, instead of forming the movable cylinder 11 in a straight tube shape and forming the guides 13 and 14 in a linear shape, they may be formed as follows: That is, the movable cylinder 11 may be formed in a circular tube shape, and the guides 13 and 14 may extend in an arc-shaped curved shape from the piston 12 inserted into the movable cylinder 11 outward through the openings at both ends of the movable cylinder 11, following the shape of the movable cylinder 11. This makes it possible to deal with an object to be sprayed or suctioned that is curved in an arc.

[0122] Although the movable cylinder 11 is provided with one nozzle communicating with each of the fluid chambers 19 and 20, multiple nozzles communicating with each fluid chamber may be provided. Also, the nozzles 24 and 25 may be provided directly on the movable cylinder 11 and communicate with the fluid chambers 19 and 20 without passing through the blocking members 15 and 16 (without passing through the communication passages 22 and 23).

[0123] The controller 45 may determine whether the moving cylinder 11 has reached the D1 restriction position or the D2 restriction position based on the count output of the timer, rather than on the output signals from the pressure sensors. However, as the number of timer cycles increases, it is inevitable that the actual position of the moving cylinder will differ from the position estimated by the timer. In this regard, it is very effective to provide a mechanism for detecting the position of the moving cylinder 11 by detecting pressure, as shown in the above embodiment.

[0124] The flow path switching valve 40 and the flow rate adjusting valves 62, 62a, 62b may be manual valves that are manually operated by an operator, instead of externally controllable solenoid valves or motorized valves, or pneumatic switching valves that use compressed air. In this case, the operator can visually confirm that the moving cylinder 11 is stopped at the D1 restriction position or the D2 restriction position, and then operate the flow path switching valve 40, and the controller 45 can be omitted. Moreover, instead of the flow rate adjusting valves 62, 62a, 62b provided in the short-circuit pipes 61, 61a, 61b, orifices may be provided.

[0125] The two outer openings 28, 32 may both be formed at different positions in one of the guides. That is, the outer openings 28, 32 may be provided in the first guide 13, the first internal flow passage 26 may be formed inside the first guide 13 so as to extend from the first outer opening 28 to the first inner opening 27, and the second internal flow passage 30 may be formed inside the first guide 13, the piston 12, and the second guide 14 so as to extend from the second outer opening 32 to the second inner opening 31. Alternatively, the outer openings 28, 32 may be provided in the second guide 14, and a first internal flow passage 26 may be formed inside the second guide 14, piston 12 and first guide 13 so as to extend from the first outer opening 28 to the first inner opening 27, and a second internal flow passage 30 may be formed inside the second guide 14 so as to extend from the second outer opening 32 to the second inner opening 31.

[0126] When the piston-cylinder mechanism 2 is disposed inside a cylindrical filter, for example, and fluid is sprayed onto or sucked from the inner peripheral surface of the filter through the nozzles 24, 25, the piston-cylinder mechanism 2 is configured as follows: That is, the piston 12 and guides 13, 14, the through holes of the closing members 15, 16, and the moving cylinder 11 are all formed to have a circular cross section so that the moving cylinder 11 rotates along the outer peripheral surfaces of the piston 12 and guides 13, 14 in addition to the reciprocating motion described above.

[0127] Furthermore, the technical concepts described in the first to eighth embodiments can be appropriately combined and used as long as no contradictions arise from the viewpoint of reducing the moving speed of the moving cylinder 11 to a desired value. For example, even if the orifice passage 34 is drilled in the piston 12, a situation can be assumed in which the moving speed of the moving cylinder 11 cannot be reduced to a desired value. In such a situation, the insufficient reduction in the moving speed can be compensated for by providing a flow control valve 62 in the short-circuit pipe 61 that short-circuits the first flow path system and the second flow path system, or by providing flow control valves 62a and 62b in the short-circuit pipes 61a and 61b that communicate with the pressure connection pipe 39 and the first external pipe 37 and the second external pipe 38. Furthermore, the technical ideas described in the first to eighth embodiments above can be used in appropriate combination as long as no contradiction occurs, from the viewpoint of detecting that the movable cylinder 11 has moved to the regulated position based on a pressure change in the flow path system.

[0128] [Summary of Examples of Embodiments, Actions, and Effects of the Present Invention] (First embodiment) This embodiment is a fluid injection or suction device 1 to 1h that injects a fluid into a target space E or suctions a fluid from the target space E through nozzles 24 and 25. The fluid injection or suction device comprises a movable cylinder 11 formed in a hollow tubular shape and having both end openings closed by closing members 15, 16, a piston 12 housed in the cylinder so as to be able to move back and forth relatively between the openings and dividing the interior of the cylinder into a first fluid chamber 19 located on the one end opening side and a second fluid chamber 20 located on the other end opening side, guides 13, 14 which support the piston and are slidably inserted into through holes provided in at least one of the closing members to guide the cylinder so as to move back and forth, a first internal flow path 26 arranged in the guide and connecting the first fluid chamber to a first external piping 37 located outside the cylinder and the guide, a second internal flow path 30 arranged in the guide and connecting the second fluid chamber to a second external piping 38 located outside the cylinder and the guide, and a nozzle which connects the first fluid chamber to a target space. the first fluid chamber and opening and closing a flow path in an appropriate position in the first fluid flow system from the short-circuit flow path to the first nozzle according to the position of the cylinder; and second fluid chamber and opening and closing a flow path in an appropriate position in the second fluid flow system from the short-circuit flow path to the second nozzle according to the position of the cylinder. The fluid injection or suction device is configured so that the connection destination of the pipe connected to the fluid pressure source 41 that generates a fluid of a predetermined pressure can be switched between the first external pipe and the second external pipe, and at least when the cylinder is in the D1 or D2 restricted state in which movement relative to the piston is restricted, the closing means is configured to substantially disconnect the nozzle from the short-circuit flow path in the flow path system to which the external pipe that is not connected to the fluid pressure source belongs.

[0129] Here, the first and second closing means are means for selectively establishing or substantially establishing communication between the first and second nozzles and the short-circuit flow path. Note that "substantially establishing communication between the nozzles and the short-circuit flow path" means that it is sufficient to block the flow of fluid between the nozzles and the short-circuit flow path to the extent that a pressure change can be detected. In this embodiment, a throttling means for throttling the flow rate is provided in the short-circuit flow path, so that the cylinder movement speed can be reduced with a simple configuration while preventing the cylinder from becoming larger and the amount of fluid injected or sucked from decreasing. According to this aspect, it is possible to detect the cylinder position without using a mechanical or optical position detection means. That is, when the cylinder moves to the D1 or D2 restriction position, the pressure in the first or second flow path system changes (returns to zero or increases or decreases at a predetermined rate), so that it is possible to detect that the cylinder has moved to the D1 or D2 restriction position based on the pressure. The fluid injection or suction device can also be operated while the cylinder is immersed in a liquid such as oil. By using pressure changes to detect the position of the cylinder, the structure of the position detection means can be simplified and the position detection means is less likely to break down, which in turn extends the maintenance intervals for the fluid injection or suction device and extends the life of the device.

[0130] (Second embodiment) In the fluid injection or suction devices 1, 1b, 1c, and 1h according to this embodiment, the shunt passage (the orifice passage 34, the shunt pipe 61) is a means for connecting the first fluid chamber 19 and the second fluid chamber 20. The openings (orifice openings 73, 74; openings 82, 83) through which the shunt flow paths face each fluid chamber may be open in the direction of reciprocating movement or in a direction intersecting the direction of reciprocating movement. In the latter case, the openings can be disposed on the outer circumferential surfaces of guides 13, 14, or at locations where closure members 15, 16 face the guides (for example, on the inner circumferential side surfaces of receiving recesses 80, 81 in FIG. 3). In either case, the closing means can be a member that moves relative to the member in which the openings are provided, and can be disposed at a location facing the openings when the cylinder moves to the D1, D2 restriction positions. In this aspect, whether a constant pressure source or a constant flow source is used as the fluid pressure source, it is possible to detect the cylinder position based on the pressure change in the flow path system.

[0131] (Third embodiment) In the fluid injection or suction device 1, 1b, 1h according to this embodiment, the short-circuit flow path is an orifice flow path 34 that connects the first fluid chamber 19 and the second fluid chamber 20 inside the movable cylinder 11, and each closing means (closing portions 71, 72: protrusions 35, 36) is arranged on each blocking member 15, 16. According to this aspect, since the shunt passage is disposed inside the cylinder, the configuration outside the cylinder can be simplified.

[0132] (Fourth embodiment) In the fluid injection or suction device 1c of this embodiment, the short-circuit flow path is a short-circuit pipe 61 that connects the first fluid chamber 19 and the second fluid chamber 20 outside the movable cylinder 11, and each closure means (closure sections 84, 85) is arranged on the guides 13, 14 or the piston 12.

[0133] The openings (openings 82, 83) through which the shunt flow paths face each fluid chamber may be arranged in the closing member or in the cylinder. The openings may be open in the direction of reciprocating movement or in a direction intersecting the direction of reciprocating movement. In the latter case, the openings can be arranged in the locations where the closing members 15, 16 face the guides (for example, on the inner peripheral side surfaces of the receiving recesses 80, 81 in FIG. 3). In either case, the closing means can be a guide or piston that moves relative to the closing member or cylinder with the openings, and can be arranged in a location that faces the openings when the cylinder moves to the D1, D2 restriction position. According to this aspect, it is possible to detect the cylinder position without using a mechanical or optical position detection means.

[0134] (Fifth embodiment) In the fluid injection or suction device 1h of this embodiment, the orifice openings 73, 74 through which the short-circuit flow path (orifice flow path 34) faces each fluid chamber 19, 20 are arranged in receiving recesses 92, 93 respectively formed as recesses in the portions facing the reciprocating movement direction, and each closing means (protrusions 35, 36) has a protrusion shape with at least its tip portion fitting into each recess, and the shape of each recess and each closing means is configured to pressurize the fluid in each recess or reverse the short-circuit flow path between the time when each closing means begins to enter each recess and the time when it reaches the D1, D2 restricted state.

[0135] According to this embodiment, the pressure change in the flow path system can be made larger than when the closing means simply closes the opening of the shunt flow path. Therefore, the detection sensitivity of the cylinder position is improved. Furthermore, when the fluid in the recess is pressurized or flows back through the shunt flow path, the movement speed of the cylinder is reduced, thereby preventing wear on the piston 12 and the closing member. Furthermore, it is preferable to open the opening facing the reciprocating movement direction, since no force other than that in the movement direction is generated in the cylinder when closing the opening. In the fluid injection or suction device 1c (FIG. 4), the openings 82 and 83 may be arranged in recesses formed in the closing members 15 and 16, and protruding closing means arranged on the piston may be inserted into the recesses.

[0136] (Sixth embodiment) In the fluid injection or suction device 1d of this embodiment, the short-circuit flow path is a short-circuit pipe 61 (or 61a, 61b) that connects the first external pipe 37 and the second external pipe 38, and each closing means (closing section 84, 85) closes each opening 86, 87 that faces each fluid chamber, of each communicating passage 22, 23 that connects each fluid chamber 19, 20 with the target space E.

[0137] In this embodiment, when the fluid pressure source is a constant flow source, the cylinder position is detected based on pressure changes within the flow path system. In this embodiment, because the two external pipes are short-circuited, the pressure in each flow path system from each external pipe to each fluid chamber cannot be completely reduced to zero. However, when one of the openings of the communicating passage facing the fluid chamber is closed, the flow rate of the fluid injected or sucked into the target space by the fluid injection or suction device is suddenly reduced. Therefore, the pressure in the flow path system to which the external pipe connected to the fluid pressure source belongs changes at a predetermined rate. In other words, when one of the openings of the communicating passage facing the fluid chamber is closed, the flow rate in one flow path system becomes approximately zero, and the flow rate in the other flow path system suddenly increases. According to this aspect, it is possible to detect the cylinder position based on the pressure change in the flow path system.

[0138] (Seventh embodiment) In the fluid injection or suction device 1e of this embodiment, the short-circuit flow path is a short-circuit pipe 61 that connects the first external pipe 37 and the second external pipe 38, and each closing means (closing section 71, 72) closes each inner opening 27, 31 where each internal flow path 26, 30 faces each fluid chamber 19, 20.

[0139] In this embodiment, when the fluid pressure source is a constant flow source, the cylinder position is detected based on pressure changes within the flow path system. In this embodiment, since both external pipes are short-circuited, the pressure in each flow path from each external pipe to each fluid chamber cannot be reduced to zero. However, when one of the internal openings is closed, the flow rate of the fluid injected or sucked into the target space by the fluid injection or suction device is suddenly reduced. Therefore, the pressure in the flow path to which the external pipe connected to the fluid pressure source belongs changes at a predetermined rate. According to this aspect, it is possible to detect the cylinder position based on the pressure change in the flow path system.

[0140] (Eighth embodiment) In the fluid injection or suction device 1f according to this embodiment, each internal flow path 26, 30 passes through the inside of the piston 12, and each inner opening 27, 31 through which each internal flow path faces each fluid chamber 19, 20 opens at a position facing the direction of reciprocating movement, and each closing means (closing portion 71, 72) is arranged in each blocking member 15, 16.

[0141] According to this aspect, since the inner opening faces the reciprocating movement direction, no force other than that in the movement direction is generated in the cylinder when the inner opening is closed.

[0142] (Ninth embodiment) In the fluid injection or suction device 1g of this embodiment, each internal flow path 26, 30 passes through the inside of the piston 12, and each inner opening 27, 31 through which each internal flow path faces each fluid chamber 19, 20 is arranged in a receiving recess 92, 93 formed as a recess at an appropriate position of the piston facing the reciprocating movement direction, each closing means (protrusion 35, 36) is a protrusion that protrudes from each blocking member 15, 16 and at least its tip portion is fitted into each recess, and the shape of each recess and each closing means is configured so that the fluid in each recess is pressurized or caused to flow back into each external piping 37, 38 from the time each closing means begins to enter each recess until the D1, D2 restriction state is reached.

[0143] According to this aspect, the pressure change in the flow path system can be made larger than when the closing means simply closes the opening of the shunt flow path. Therefore, the detection sensitivity of the cylinder position is improved. Furthermore, when pressurizing the fluid in the recess or causing the shunt flow path to flow backward, the movement speed of the cylinder is reduced, thereby preventing wear on the piston and the closing member.

[0144] (Tenth embodiment) The fluid injection or suction devices 1 to 1h according to this embodiment include an electric pump as a fluid pressure source 41, and a controller 45 that acquires information related to the current flowing through the electric pump. The controller determines whether the moving cylinder 11 is in the D1 or D2 restricted state based on information related to the current that fluctuates based on changes in the discharge amount of fluid discharged by the fluid pressure source and / or changes in the discharge pressure. The electric pump may be a constant pressure source, a constant flow source, or a general pump that is not configured to maintain a constant discharge pressure and discharge flow rate. The information regarding the current may be the value of the current flowing through the electric pump, or the value of the amount of power consumed by the electric pump. The electric pump is driven by a load that corresponds to the fluid discharge rate and / or discharge pressure. Therefore, the electric pump consumes power that corresponds to the load that fluctuates when the cylinder transitions to the restricted state. According to this aspect, when an electric pump is used as the fluid pressure source, the position of the cylinder can be detected based on information relating to the value of the current flowing through the electric pump. [Explanation of symbols]

[0145] 1, 1b to 1h...fluid device, 2...piston-cylinder mechanism, 3...external piping system, 4...control system, 11...moving cylinder, 12...piston, 13...first guide, 13, 14...guide, 14...second guide, 15...first closing member, 16...second closing member, 17...sealing member, 18...sealing member, 19...first fluid chamber, 20...second fluid chamber, 21...sealing member, 22...first communication passage, 23...second communication passage, 24...first nozzle, 25...second nozzle, 26...first internal flow path, 27...first inner opening, 28...first outer opening, 29...first connector, 30...second internal flow path, 31...second inner opening, 32...second outer opening, 33...second connector, 34...orifice flow path, 35...first protrusion, 36...second protrusion, 37...first external piping, 38...second external piping, 39...pressure connecting pipe, 40...flow path switching valve, 40a... Two-way solenoid valve, 40a, 40b... two-way solenoid valve, 40b... two-way solenoid valve, 41... fluid pressure source, 42... first pressure detector, 43... second pressure detector, 44... third pressure detector, 45... controller, 46... relief valve, 61... short-circuit pipe, 61a... first short-circuit pipe, 61b... second short-circuit pipe, 62... flow rate adjustment valve, 62a... first flow rate adjustment valve, 62b... second flow rate adjustment valve, 63... communication passage, 64... connector 65...communicating passage, 66...connector, 71...first closing portion, 72...second closing portion, 73...first orifice opening, 74...second orifice opening, 78...first large diameter portion, 79...second large diameter portion, 80...first receiving recess, 81...second receiving recess, 82, 83...opening, 84...first closing portion, 85...second closing portion, 86, 87...opening, 92...first receiving recess, 93...second receiving recess, 94, 95...gap, E...target space

Claims

1. A fluid injection or suction device that injects a fluid into a target space or suctions a fluid from the target space through a nozzle, a cylinder formed in a hollow tubular shape, with both end openings closed by closing members; a piston accommodated in the cylinder so as to be capable of relatively reciprocating movement between the openings, and dividing the interior of the cylinder into a first fluid chamber located on one end opening side and a second fluid chamber located on the other end opening side; a guide that supports the piston and is slidably inserted into a through hole provided in at least one of the closing members to guide the cylinder so as to reciprocate; a first internal flow passage disposed within the guide and communicating with the first fluid chamber and a first external pipe located outside the cylinder and the guide; a second internal flow passage disposed within the guide and communicating with the second fluid chamber and a second external pipe located outside the cylinder and the guide; a first nozzle among the nozzles that communicates the first fluid chamber with the target space; a second nozzle among the nozzles that communicates the second fluid chamber with the target space; a short-circuit flow path that short-circuits a first flow path system extending from the first external pipe to the first nozzle and a second flow path system extending from the second external pipe to the second nozzle; a throttle means disposed in the shunt passage for throttling the flow rate of the fluid; a first closing means disposed in the first fluid chamber and configured to open and close a flow path in the first flow path system from the shunt flow path to the first nozzle in accordance with the position of the cylinder; a second closing means disposed in the second fluid chamber and configured to open and close a flow path in the second flow path system from the short-circuit flow path to the second nozzle in accordance with the position of the cylinder; a connection destination of a pipe communicating with a fluid pressure source that generates a fluid of a predetermined pressure can be switched between the first external pipe and the second external pipe, a fluid injection or suction device, wherein the closing means is configured to substantially disconnect the nozzle from the short-circuit flow path in the flow path system to which the external piping not communicating with the fluid pressure source belongs, at least when the cylinder is in a restricted state in which movement relative to the piston is restricted.

2. The fluid ejection or suction device according to claim 1 , wherein the shunt passage is a means for connecting the first fluid chamber and the second fluid chamber.

3. 3. The fluid injection or suction device according to claim 2, wherein the short-circuit flow path is an orifice flow path that connects the first fluid chamber and the second fluid chamber inside the cylinder, and each of the closing means is disposed in each of the blocking members.

4. the short-circuit flow path is a short-circuit pipe that connects the first fluid chamber and the second fluid chamber outside the cylinder, 3. A fluid injection or suction device according to claim 2, wherein each of said closure means is arranged on each of said guides or said pistons.

5. The openings of the shunt flow paths facing the respective fluid chambers are disposed in recesses formed in the portions facing the reciprocating movement direction, Each of the closing means has a protrusion shape, at least a tip portion of which fits into each of the recesses, 5. The fluid injection or suction device according to claim 3, wherein the shapes of the recesses and the closing means are configured to pressurize the fluid in the recesses or reverse the short-circuit flow path between the time when the closing means starts to enter the recesses and the time when the closing means reaches the restricted state.

6. the short-circuit flow path is a short-circuit pipe that connects the first external pipe and the second external pipe in communication with each other, 2. The fluid injection or suction device according to claim 1, wherein each of the closing means closes an opening of each of the communication passages that connects each of the fluid chambers with the target space, the opening facing the corresponding fluid chamber.

7. the short-circuit flow path is a short-circuit pipe that connects the first external pipe and the second external pipe in communication with each other, 2. The fluid ejection or suction device according to claim 1, wherein the closing means closes internal openings through which the internal flow paths face the fluid chambers.

8. Each of the internal flow paths passes through the inside of the piston, and each of the internal flow paths has an inner opening facing the corresponding fluid chamber, the inner opening being open at a position facing the reciprocating movement direction, 8. A fluid injection or suction device according to claim 7, wherein each said closure means is disposed on each said obstruction member.

9. each of the internal flow paths passes through the inside of the piston, and each of the internal flow paths has an inner opening facing each of the fluid chambers, the inner opening being disposed in a recess formed in an appropriate position of the piston facing the reciprocating movement direction, Each of the closing means is a projection projecting from each of the blocking members, and at least a tip end thereof is fitted into each of the recesses, 8. The fluid injection or suction device according to claim 7, wherein the shapes of the recesses and the closing means are configured to pressurize the fluid in the recesses or cause it to flow back into the external pipes between the time when the closing means starts to enter the recesses and the time when the regulating state is reached.

10. 2. The fluid injection or suction device according to claim 1, further comprising: an electric pump as the fluid pressure source; and a controller that acquires information related to a current flowing through the electric pump, wherein the controller determines whether the cylinder is in the restricted state based on information related to the current that fluctuates based on a change in the discharge amount of fluid discharged by the fluid pressure source and / or a change in the discharge pressure.

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