Intermittent air discharge fluid circuit
The intermittent air discharge fluid circuit addresses the issue of unstable operation in existing devices by ensuring that the main valve only switches after the pilot valve has stabilized and by managing air supply to prevent pressure drops, resulting in stable operation of both valves.
Patent Information
- Application Number
- JP2022162013
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2022-10-07
- Publication Date
- 2025-03-18
- Estimated Expiration
- 2042-10-07
AI Technical Summary
In existing intermittent air discharge devices, there is a risk of unstable operation of the main valve and pilot valve due to simultaneous supply of compressed air to both valves, leading to potential premature switching and pressure drop effects.
The proposed intermittent air discharge fluid circuit includes a main valve with a discharge pilot chamber and a pilot valve with an air supply pilot chamber, where the main valve is switched between two positions based on the state of the pilot valve, ensuring that the main valve only switches after the pilot valve has stabilized, and air supply is managed to prevent pressure drops from affecting valve operation.
This solution ensures stable operation of the main valve and pilot valve by ensuring that the main valve is only switched after the pilot valve has completed its cycle, and by managing air supply to prevent pressure drops from interfering with valve operation.
Smart Images
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Abstract
Description
[Technical field]
[0001] The present invention relates to an intermittent air-discharging fluid circuit for intermittently discharging air such as compressed air. [Background technology]
[0002] 2. Description of the Related Art It is conventionally known to use a fluid circuit including an air-operated main valve and an air-operated pilot valve in an apparatus that intermittently discharges compressed air toward an object such as a workpiece.
[0003] For example, Patent Document 1 describes an intermittent air discharge device having a main valve that switches between communication and cut-off between an air intake port and a discharge port, and a pilot valve that switches between a state in which compressed air is supplied to a discharge pilot chamber of the main valve and a state in which it is not supplied. In this intermittent air discharge device, compressed air supplied to the air intake port is supplied to the discharge pilot chamber of the main valve and the air supply stop pilot chamber of the pilot valve. [Prior art documents] [Patent documents]
[0004] [Patent Document 1] Patent No. 6289358 Summary of the Invention [Problem to be solved by the invention]
[0005] In the intermittent air discharge device of Patent Document 1, the compressed air supplied to the air intake port is simultaneously supplied to the pilot chamber of the main valve and the pilot chamber of the pilot valve, so there is a possibility that the pilot valve will switch before the main valve switches. In addition, the compressed air supplied to the air intake port is discharged from the discharge port, so there is a possibility that compressed air with a pressure drop will be supplied to the pilot chamber of the main valve and the pilot chamber of the pilot valve. Due to these factors, there is a risk that the operation of the main valve and the pilot valve will become unstable.
[0006] The present invention aims to solve the above-mentioned problems. [Means for solving the problem]
[0007] The present invention relates to an intermittent air discharge fluid circuit for intermittently discharging air from a discharge port of an air discharge device, and includes a main valve having a discharge pilot chamber and a pilot valve having an air supply pilot chamber. The main valve is switched between a first position where the air supply pilot chamber is connected to an air supply source and the discharge port is open to the atmosphere, and a second position where the air supply pilot chamber is open to the atmosphere and the discharge port is connected to the air supply source. The pilot valve is switched between the first position where the discharge pilot chamber is open to the atmosphere, and the second position where the discharge pilot chamber is connected to the air supply source. Effect of the Invention
[0008] According to the fluid circuit for intermittent air discharge of the present invention, the main valve is not switched until the pilot valve is switched. Furthermore, even if a pressure drop occurs due to the discharge of air, the pressure drop does not affect the operation of the pilot valve and the main valve. Therefore, stable operation of the main valve and the pilot valve is ensured. [Brief description of the drawings]
[0009] [Figure 1] FIG. 1 is a diagram showing a fluid circuit for intermittent air discharge according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing a state in which the pilot valve in the intermittent air discharge fluid circuit in FIG. 1 has been switched. [Diagram 3] FIG. 3 is a diagram showing a state in which the main valve in the intermittent air discharge fluid circuit of FIG. 2 has been switched. [Figure 4] FIG. 4 is a diagram showing a state in which the pilot valve in the intermittent air discharge fluid circuit of FIG. 3 has been switched. [Diagram 5] FIG. 5 is a diagram showing a fluid circuit for intermittent air discharge according to a second embodiment of the present invention. [Figure 6] FIG. 6 is a diagram showing a fluid circuit for intermittent air discharge according to a third embodiment of the present invention. [Figure 7] FIG. 7 is a diagram showing a specific example of the structure of the main valve and the pilot valve of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0010] (First embodiment) A fluid circuit 10 for intermittent air discharge according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 4. FIG.
[0011] 1, the intermittent air discharge fluid circuit 10 includes a main valve 12 equipped with a discharge pilot chamber 14, and a pilot valve 18 equipped with an air supply pilot chamber 20. The intermittent air discharge fluid circuit 10 is used, for example, in an air discharge device (not shown) that intermittently discharges air toward a workpiece and removes foreign matter such as dust adhering to the workpiece.
[0012] A first communication flow path 24 and a second communication flow path 26 are arranged between the main valve 12 and the pilot valve 18. First to fourth air supply flow paths 28a to 28d are arranged between the main valve 12, the pilot valve 18, and the air supply source 30. One end of the first air supply flow path 28a is connected to the air supply source 30, and the other end of the first air supply flow path 28a is connected to the second air supply flow path 28b, the third air supply flow path 28c, and the fourth air supply flow path 28d. The second air supply flow path 28b and the third air supply flow path 28c are connected to the main valve 12. The fourth air supply flow path 28d is connected to the pilot valve 18.
[0013] The third air supply flow path 28c is a flow path for supplying air to the air supply pilot chamber 20 of the pilot valve 18. The fourth air supply flow path 28d is a flow path for supplying air to the discharge pilot chamber 14 of the main valve 12. One end of the first air supply flow path 28a is always connected to the air supply source 30, but may be connected to the air supply source 30 via a solenoid valve that switches between connection and disconnection with the air supply source 30.
[0014] The main valve 12 has first to fifth ports 16a to 16e. The first port 16a is connected to the discharge port 36 of the air discharge device. The second port 16b is connected to the air supply pilot chamber 20 of the pilot valve 18 via the first connecting flow path 24. The third port 16c is connected to the air supply source 30 via the second air supply flow path 28b and the first air supply flow path 28a. The fourth port 16d is connected to the first exhaust port 32. The fifth port 16e is connected to the air supply source 30 via the third air supply flow path 28c and the first air supply flow path 28a.
[0015] The main valve 12 can be switched between a first position and a second position. When the main valve 12 is in the first position, the first port 16a and the fourth port 16d communicate with each other, and the second port 16b and the fifth port 16e communicate with each other (see FIGS. 1 and 2). When the main valve 12 is in the second position, the first port 16a and the third port 16c communicate with each other, and the second port 16b and the fourth port 16d communicate with each other (see FIGS. 3 and 4).
[0016] The main valve 12 switches to the first position when air is exhausted from the discharge pilot chamber 14, and switches to the second position when air is supplied to the discharge pilot chamber 14. When the main valve 12 is in the first position, the air supply pilot chamber 20 of the pilot valve 18 is connected to the air supply source 30, and the discharge port 36 is opened to the atmosphere through the first exhaust port 32. When the main valve 12 is in the second position, the air supply pilot chamber 20 of the pilot valve 18 is opened to the atmosphere through the first exhaust port 32, and the discharge port 36 is connected to the air supply source 30.
[0017] The pilot valve 18 has first to third ports 22a to 22c. The first port 22a is connected to the discharge pilot chamber 14 of the main valve 12 via a second connecting passage 26. The second port 22b is connected to the air supply source 30 via a fourth air supply passage 28d and a first air supply passage 28a. The third port 22c is connected to a second exhaust port 34.
[0018] The pilot valve 18 is switched between a first position and a second position. When the pilot valve 18 is in the first position, the first port 22a and the third port 22c communicate with each other, and the communication between the first port 22a and the second port 22b is blocked (see FIGS. 1 and 4). When the pilot valve 18 is in the second position, the first port 22a and the second port 22b communicate with each other, and the communication between the first port 22a and the third port 22c is blocked (see FIGS. 2 and 3).
[0019] The pilot valve 18 switches to the first position when air is exhausted from the air supply pilot chamber 20, and switches to the second position when air is supplied to the air supply pilot chamber 20. When the pilot valve 18 is in the first position, the discharge pilot chamber 14 of the main valve 12 is opened to the atmosphere through the second exhaust port 34. When the pilot valve 18 is in the second position, the discharge pilot chamber 14 of the main valve 12 is connected to the air supply source 30.
[0020] Reference numeral 70 denotes an air chamber for applying air pressure against the discharge pilot chamber 14, and reference numeral 82 denotes a pilot air chamber for applying air pressure against the intake pilot chamber 20. Air is supplied to the air chamber 70 and the pilot air chamber 82 from the air supply source 30, regardless of the switching positions of the main valve 12 and the pilot valve 18.
[0021] Next, the operation of the intermittent air discharge fluid circuit 10 will be described. As shown in Fig. 1, the initial state is a state in which the main valve 12 is in the first position and the pilot valve 18 is in the first position. It is assumed that one end of the first air supply flow path 28a is constantly connected to the air supply source 30. In the initial state, the air supply source 30 is stopped.
[0022] When the air supply source 30 starts operating, air from the air supply source 30 is supplied to the air supply pilot chamber 20 of the pilot valve 18 via the first air supply flow path 28a, the third air supply flow path 28c, the main valve 12, and the first connecting flow path 24. This causes the pilot valve 18 to switch from the first position to the second position, as shown in Fig. 2. Note that when one end of the first air supply flow path 28a is connected to the air supply source 30 via a solenoid valve, the above phrase "the air supply source 30 starts operating" should be read as "the solenoid valve switches to the open position, and the first air supply flow path 28a is connected to the air supply source 30", assuming that the air supply source 30 is operating.
[0023] When the pilot valve 18 is switched to the second position, air from the air supply source 30 is supplied to the discharge pilot chamber 14 of the main valve 12 through the first air supply passage 28a, the fourth air supply passage 28d, the pilot valve 18, and the second connecting passage 26. This causes the main valve 12 to switch from the first position to the second position, as shown in Fig. 3.
[0024] When the main valve 12 switches to the second position, air from the air supply source 30 passes through the first air supply flow path 28a, the second air supply flow path 28b, and the main valve 12, and is discharged from the discharge port 36. At the same time, air in the air supply pilot chamber 20 of the pilot valve 18 passes through the first connecting flow path 24 and the main valve 12, and is exhausted from the first exhaust port 32. This causes the pilot valve 18 to switch from the second position to the first position, as shown in Fig. 4.
[0025] When the pilot valve 18 switches to the first position, air in the discharge pilot chamber 14 of the main valve 12 passes through the second connecting flow path 26 and the pilot valve 18, and is exhausted from the second exhaust port 34. This causes the main valve 12 to switch from the second position to the first position, as shown in Fig. 1. While the air supply source 30 is operating, the above operation is repeated periodically, and air is intermittently discharged from the discharge port 36. Note that, when one end of the first air supply flow path 28a is connected to the air supply source 30 via a solenoid valve, the above phrase "while the air supply source 30 is operating" should be read as "while the solenoid valve is in the open position".
[0026] According to the fluid circuit 10 for intermittent air discharge according to this embodiment, the main valve 12 in the first position does not switch to the second position until the pilot valve 18 has switched from the first position to the second position. Also, the main valve 12 in the second position does not switch to the first position until the pilot valve 18 has switched from the second position to the first position. This ensures stable operation of the main valve 12.
[0027] Furthermore, after the main valve 12 is switched to the first position, when air from the air supply source 30 is supplied to the intake pilot chamber 20 of the pilot valve 18 and the discharge pilot chamber 14 of the main valve 12, it is not discharged from the discharge port 36. Therefore, no pressure drop occurs in the air supplied to the intake pilot chamber 20 of the pilot valve 18 and the discharge pilot chamber 14 of the main valve 12.
[0028] On the other hand, after the main valve 12 is switched to the second position, air from the air supply source 30 is discharged from the discharge port 36 and is also supplied to the pilot air chamber 82 of the pilot valve 18 and the air chamber 70 of the main valve 12. At this time, air with a pressure drop may be supplied to the pilot air chamber 82 and the air chamber 70, but the effect of this pressure drop on the next switching (switching from the second position to the first position) is considered to be extremely small. This is because when the air in the air supply pilot chamber 20 of the pilot valve 18 and the discharge pilot chamber 14 of the main valve 12 is exhausted and opened to the atmosphere, there is almost no residual pressure that biases the pilot valve 18 and the main valve 12 to the second position. Since there is almost no residual pressure, as long as air is supplied to the pilot air chamber 82 and the air chamber 70, the main valve 12 and the pilot valve 18 are reliably switched to the first position. From the above, stable operation of the main valve 12 and the pilot valve 18 is ensured.
[0029] In the above embodiment, air from the air supply 30 is used to switch the main valve 12 and the pilot valve 18 from the second position to the first position. Instead, a biasing member such as a spring or a combination of air and a spring may be used. In this case, the effect of the pressure drop can be further eliminated.
[0030] Second embodiment Next, a fluid circuit 40 for intermittent air discharge according to a second embodiment of the present invention will be described with reference to Fig. 5. The fluid circuit 40 for intermittent air discharge according to the second embodiment differs from the fluid circuit 10 for intermittent air discharge according to the first embodiment in that a circuit for adjusting the operation frequency of the main valve 12 and the pilot valve 18 is added. Note that components that are the same as or equivalent to those in the fluid circuit 10 for intermittent air discharge according to the first embodiment are given the same reference numerals and detailed description will be omitted.
[0031] A first variable throttle valve 42 is disposed in the first connecting flow path 24, and a first check valve 44 is disposed in a flow path bypassing the first variable throttle valve 42. That is, the first check valve 44 is disposed in parallel with the first variable throttle valve 42. The first check valve 44 allows air to flow from the air supply pilot chamber 20 of the pilot valve 18 toward the second port 16b of the main valve 12, and blocks air from flowing from the second port 16b of the main valve 12 toward the air supply pilot chamber 20 of the pilot valve 18. For this reason, the flow rate of air supplied from the air supply source 30 to the air supply pilot chamber 20 of the pilot valve 18 is limited according to the flow path area set by the first variable throttle valve 42.
[0032] A second variable throttle valve 46 is disposed in the second communication flow path 26, and a second check valve 48 is disposed in a flow path bypassing the second variable throttle valve 46. That is, the second check valve 48 is disposed in parallel with the second variable throttle valve 46. The second check valve 48 allows air to flow from the first port 22a of the pilot valve 18 toward the discharge pilot chamber 14 of the main valve 12, and blocks air from flowing from the discharge pilot chamber 14 of the main valve 12 toward the first port 22a of the pilot valve 18. For this reason, the flow rate of air discharged from the discharge pilot chamber 14 of the main valve 12 toward the second exhaust port 34 is limited according to the flow path area set by the second variable throttle valve 46.
[0033] The smaller the flow rate of air supplied to the air intake pilot chamber 20, the slower the rate of pressure rise in the air intake pilot chamber 20, and the longer the time (T1) from when the main valve 12 switches to the first position until the pilot valve 18 switches to the second position. The smaller the flow rate of air discharged from the discharge pilot chamber 14, the longer the time (T2) from when the pilot valve 18 switches to the first position until the main valve 12 switches to the first position.
[0034] The longer T1 and T2 are, the less frequently the main valve 12 and the pilot valve 18 operate. Since T1 is included in the time period when air is not discharged from the discharge port 36, the longer T1 is, the smaller the flow rate of air discharged from the discharge port 36 is. On the other hand, since T2 is included in the time period when air is discharged from the discharge port 36, the longer T2 is, the larger the flow rate of air discharged from the discharge port 36 is. In order to increase the flow rate of air discharged from the discharge port 36, it is sufficient to shorten T1 and lengthen T2. In other words, in order to increase the flow rate of air discharged from the discharge port 36, it is sufficient to increase the flow path area set by the first variable throttle valve 42 and decrease the flow path area set by the second variable throttle valve 46.
[0035] According to the fluid circuit 40 for intermittent air discharge of this embodiment, the operating frequency of the main valve 12 and the pilot valve 18 can be adjusted, and the flow rate of air discharged from the discharge port 36 can also be adjusted.
[0036] 7 shows specific examples of the structures of the main valve 12 and the pilot valve 18. The main valve 12 includes a body 60, a sleeve 62, and a spool 64. The pilot valve 18 includes a pilot body 74, a pilot sleeve 76, and a pilot spool 78.
[0037] The body 60 includes the first to fifth ports 16a to 16e. The sleeve 62 is fixed inside the body 60. The spool 64 slides inside the sleeve 62, thereby changing the connection relationship of the first to fifth ports 16a to 16e. As shown in FIG. 7, when the spool 64 is at the left end of its travel, the first port 16a and the fourth port 16d communicate with each other, and the second port 16b and the fifth port 16e communicate with each other. That is, FIG. 7 shows that the main valve 12 is in the first position. When the spool 64 moves to the right, the first port 16a and the third port 16c communicate with each other, and the second port 16b and the fourth port 16d communicate with each other. That is, the main valve 12 switches to the second position.
[0038] A first piston 66 abuts against the left end of the spool 64. The discharge pilot chamber 14 is formed to the left of the first piston 66. A second piston 68 abuts against the right end of the spool 64. An air chamber 70 that communicates with the third port 16c is formed to the right of the second piston 68. A spring 72 that urges the second piston 68 leftward is disposed in the air chamber 70.
[0039] The pilot body 74 includes the first to third ports 22a to 22c. The pilot sleeve 76 is fixed inside the pilot body 74. The connection relationship of the first to third ports 22a to 22c changes as the pilot spool 78 slides inside the pilot sleeve 76. As shown in FIG. 7, when the pilot spool 78 is at the right end of its travel, the first port 22a and the third port 22c communicate with each other. That is, FIG. 7 shows that the pilot valve 18 is in the first position. When the pilot spool 78 moves leftward, the first port 22a and the second port 22b communicate with each other, and the pilot valve 18 switches to the second position.
[0040] A pilot piston 80 abuts against the right end of the pilot spool 78. The air supply pilot chamber 20 is formed to the right of the pilot piston 80. A pilot air chamber 82 that communicates with the second port 22b is formed to the left of the pilot spool 78. A pilot spring 84 that urges the pilot spool 78 to the right is disposed in the pilot air chamber 82. Note that the spring 72 and the pilot spring 84 are not necessarily required components.
[0041] The structural example in Fig. 7 can also be applied to the intermittent air discharge fluid circuit 10 according to the first embodiment and the intermittent air discharge fluid circuit 50 according to the third embodiment described below. In the structural example in Fig. 7, the second port 22b of the pilot valve 18 is connected to the air supply source 30 via the fourth air supply passage 28d and the third air supply passage 28c.
[0042] Third embodiment Next, an intermittent air discharge fluid circuit 50 according to a third embodiment of the present invention will be described with reference to Fig. 6. The intermittent air discharge fluid circuit 50 according to the third embodiment differs from the intermittent air discharge fluid circuit 40 according to the second embodiment in that it includes a first air supply source 54 connected to the main valve 12 and a second air supply source 56 connected to the main valve 12 and the pilot valve 18. The intermittent air discharge fluid circuit 50 according to the third embodiment also differs from the intermittent air discharge fluid circuit 40 according to the second embodiment in that it includes an external pilot valve 58. Note that the same or equivalent components as those in the intermittent air discharge fluid circuit 40 according to the second embodiment are denoted by the same reference symbols.
[0043] Between the main valve 12 and the pilot valve 18, the first linking flow path 24 and the second linking flow path 26 are arranged. Between the main valve 12 and the first air supply source 54, the first air supply flow path 52a is arranged. The first air supply flow path 52a is always connected to the first air supply source 54. Between the main valve 12, the pilot valve 18, and the second air supply source 56, the second air supply flow path 52b, the third air supply flow path 52c, and the fourth air supply flow path 52d are arranged. One end of the second air supply flow path 52b is connected to the second air supply source 56, and the other end of the second air supply flow path 52b is connected to the third air supply flow path 52c and the fourth air supply flow path 52d. The third air supply flow path 52c is connected to the main valve 12. The fourth air supply flow path 52d is connected to the pilot valve 18. An external pilot valve 58 is arranged in the middle of the second air supply flow path 52b.
[0044] The main valve 12 has first to fifth ports 16a to 16e. The first port 16a is connected to the discharge port 36. The second port 16b is connected to the air supply pilot chamber 20 of the pilot valve 18 via the first connecting flow path 24. The third port 16c is connected to the first air supply source 54 via the first air supply flow path 52a. The fourth port 16d is connected to the first exhaust port 32. The fifth port 16e is connected to the second air supply source 56 via the third air supply flow path 52c and the second air supply flow path 52b.
[0045] The pilot valve 18 has first to third ports 22a to 22c. The first port 22a is connected to the discharge pilot chamber 14 of the main valve 12 via a second connecting passage 26. The second port 22b is connected to the second air supply source 56 via a fourth air supply passage 52d and a second air supply passage 52b. The third port 22c is connected to the second exhaust port 34.
[0046] The main valve 12 is switched between a first position and a second position. When the main valve 12 is in the first position, the first port 16a and the fourth port 16d communicate with each other, and the second port 16b and the fifth port 16e communicate with each other. When the main valve 12 is in the second position, the first port 16a and the third port 16c communicate with each other, and the second port 16b and the fourth port 16d communicate with each other.
[0047] The main valve 12 switches to the first position when air is exhausted from the discharge pilot chamber 14, and switches to the second position when air is supplied to the discharge pilot chamber 14. When the main valve 12 is in the first position, the air supply pilot chamber 20 of the pilot valve 18 is connected to a second air supply source 56 via an external pilot valve 58, and the discharge port 36 is opened to the atmosphere through the first exhaust port 32. When the main valve 12 is in the second position, the air supply pilot chamber 20 of the pilot valve 18 is opened to the atmosphere through the first exhaust port 32, and the discharge port 36 is connected to the first air supply source 54.
[0048] The pilot valve 18 is switched between a first position and a second position. When the pilot valve 18 is in the first position, the first port 22a and the third port 22c communicate with each other, and communication between the first port 22a and the second port 22b is blocked. When the pilot valve 18 is in the second position, the first port 22a and the second port 22b communicate with each other, and communication between the first port 22a and the third port 22c is blocked.
[0049] The external pilot valve 58 is configured as a two-port valve and is switched between a closed position and an open position. When the external pilot valve 58 is in the open position, the second air supply source 56 is connected to the fifth port 16e of the main valve 12 and the second port 22b of the pilot valve 18. When the external pilot valve 58 is in the closed position, the connection between the second air supply source 56 and the fifth port 16e of the main valve 12 is cut off, and the connection between the second air supply source 56 and the second port 22b of the pilot valve 18 is cut off. The external pilot valve 58 controls the start and stop of the air discharge operation from the discharge port 36.
[0050] The pilot valve 18 switches to the first position when air is exhausted from the air supply pilot chamber 20, and switches to the second position when air is supplied to the air supply pilot chamber 20. When the pilot valve 18 is in the first position, the discharge pilot chamber 14 of the main valve 12 is opened to the atmosphere through the second exhaust port 34. When the pilot valve 18 is in the second position and the external pilot valve 58 is in the open position, the discharge pilot chamber 14 of the main valve 12 is connected to the second air supply source 56.
[0051] Next, the operation of the intermittent air discharge fluid circuit 50 will be described. In the initial state, the first air supply source 54 and the second air supply source 56 are operating, and the external pilot valve 58 is in the closed position. In addition, the main valve 12 is in the first position, and the pilot valve 18 is in the first position. No air is discharged from the discharge port 36.
[0052] When the external pilot valve 58 is in the open position, air from the second air supply source 56 is supplied to the air supply pilot chamber 20 of the pilot valve 18 via the second air supply passage 52b, the third air supply passage 52c, the main valve 12, and the first connecting passage 24. This causes the pilot valve 18 to switch from the first position to the second position.
[0053] When the pilot valve 18 is switched to the second position, air from the second air supply source 56 is supplied to the discharge pilot chamber 14 of the main valve 12 through the second air supply passage 52b, the fourth air supply passage 52d, the pilot valve 18, and the second connecting passage 26. This causes the main valve 12 to switch from the first position to the second position.
[0054] When the main valve 12 switches to the second position, air from the first air supply source 54 passes through the first air supply flow path 52a and the main valve 12, and is discharged from the discharge port 36. At the same time, air in the air supply pilot chamber 20 of the pilot valve 18 passes through the first connecting flow path 24 and the main valve 12, and is exhausted from the first exhaust port 32. This switches the pilot valve 18 from the second position to the first position.
[0055] When the pilot valve 18 switches to the first position, air in the discharge pilot chamber 14 of the main valve 12 passes through the second connecting flow path 26 and the pilot valve 18, and is exhausted from the second exhaust port 34. This switches the main valve 12 from the second position to the first position. While the external pilot valve 58 is in the open position, the above operation is repeated cyclically, and air is intermittently discharged from the discharge port 36.
[0056] When the external pilot valve 58 switches to the closed position, the supply of air to the second port 22b of the pilot valve 18 is stopped. Therefore, when the pilot valve 18 is in the second position, the supply of air to the discharge pilot chamber 14 of the main valve 12 is stopped. When the supply of air to the discharge pilot chamber 14 of the main valve 12 is stopped, if the main valve 12 is in the second position and air is being discharged from the discharge port 36, the exhaust of air from the air supply pilot chamber 20 of the pilot valve 18 progresses, and the pilot valve 18 switches to the first position.
[0057] When the pilot valve 18 switches to the first position, the air in the discharge pilot chamber 14 of the main valve 12 is quickly exhausted, the main valve 12 switches to the first position, and the discharge of air from the discharge port 36 stops. After that, air is no longer supplied to the discharge pilot chamber 14 of the main valve 12, so the state in which air is not discharged from the discharge port 36 is reliably maintained.
[0058] According to the intermittent air discharge fluid circuit 50 of this embodiment, the flow rate of air discharged from the discharge port 36 can be determined based on the capacity of the first air supply source 54. In addition, the flow rate of air supplied to the discharge pilot chamber 14 of the main valve 12 and the flow rate of air supplied to the air supply pilot chamber 20 of the pilot valve 18 can be determined based on the capacity of the second air supply source 56. For this reason, this is useful when discharging a large flow rate of air from the discharge port 36.
[0059] The present invention is not limited to the above-described embodiment, and various configurations can be adopted without departing from the gist of the present invention. [Explanation of symbols]
[0060] 10, 40, 50...Intermittent air discharge fluid circuit 12...Main valve 14...Discharge pilot chamber 18: Pilot valve 20: Air supply pilot chamber 24...First connecting flow path (flow path) 26...Second connecting flow path (flow path) 30: Air supply source 36: Discharge port 42...First variable throttle valve (first throttle valve) 44...First check valve 46...Second variable throttle valve (second throttle valve) 48...Second check valve 54...First air supply source 56...Second air supply source 58…External pilot valve
Claims
1. An intermittent air discharge fluid circuit for intermittently discharging air from a discharge port of an air discharge device toward a workpiece, a main valve having a discharge pilot chamber and a pilot valve having an air supply pilot chamber, the main valve being switched between a first position in which the air supply pilot chamber is connected to an air supply source and the discharge port is open to the atmosphere and a second position in which the air supply pilot chamber is open to the atmosphere and the discharge port is connected to the air supply source, the pilot valve being switched between the first position in which the discharge pilot chamber is open to the atmosphere and a second position in which the discharge pilot chamber is connected to the air supply source, an intermittent air discharge fluid circuit, in which the main valve in the first position is not switched to the second position unless the pilot valve has been switched from the first position to the second position, the main valve in the second position is not switched to the first position unless the pilot valve has been switched from the second position to the first position, and after the main valve is switched to the first position, air from the air supply source is supplied to the air supply pilot chamber of the pilot valve and the discharge pilot chamber of the main valve, and is not discharged from the discharge port.
2. 2. The fluid circuit for intermittent air discharge according to claim 1, an intermittent air discharge fluid circuit, in which a first throttle valve is disposed in a flow path connecting the air supply pilot chamber and the main valve, and a second throttle valve is disposed in a flow path connecting the discharge pilot chamber and the pilot valve.
3. 3. The fluid circuit for intermittent air discharge according to claim 2, a first check valve disposed in parallel with the first throttle valve, and a second check valve disposed in parallel with the second throttle valve;
4. 2. The fluid circuit for intermittent air discharge according to claim 1, an intermittent air discharge fluid circuit in which the discharge port, the air supply pilot chamber and the discharge pilot chamber are connected to a same air supply source;
5. 2. The fluid circuit for intermittent air discharge according to claim 1, an intermittent air discharge fluid circuit, the discharge port being connected to a first air supply source, and the air supply pilot chamber and the discharge pilot chamber being connected to a second air supply source;
6. 6. The fluid circuit for intermittent air discharge according to claim 5, The air supply pilot chamber and the air discharge pilot chamber are connected to the second air supply source via an external pilot valve.
Citation Information
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